The Shawnee Hills / Southern Illinois (Little Egypt) spans USDA hardiness zone 7a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Illinois's warmest, longest-season ground — and the only unglaciated, hilly corner of the state. Below the Ohio–Mississippi confluence, all 11 counties sit in USDA zone 7a with 220–244 frost-free days (Alexander reaches 244), roughly a full zone warmer and a month longer than the central-Illinois 5b–6a prairie averaged onto the state page. The Shawnee Hills terrain — sandstone ridges, Shawnee National Forest, and the Shawnee Hills AVA (27 CFR §9.206) — trades flat row-crop prairie for slopes, orchards, and vineyards: Union County's Cobden–Anna peach and apple belt and the Shawnee Hills wine trail. Growers here plant weeks earlier and can carry crops that fail statewide — figs, longer-season melons, and tree peaches. Well-matched crops include sweet corn, tomato, pumpkin, and apple, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
The Shawnee Hills / Southern Illinois (Little Egypt) spans Illinois.
Your yard isn't all of the Shawnee Hills / Southern Illinois (Little Egypt).
The Shawnee Hills / Southern Illinois (Little Egypt) spans USDA zones 7a, but your parcel sits in exactly one — and slope, tree cover, and low spots nudge it further. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Shawnee Hills / Southern Illinois (Little Egypt) — soil, climate, flood, and parcel records. How we handle your address.
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The Shawnee Hills / Southern Illinois (Little Egypt) — the short answer
The Shawnee Hills / Southern Illinois (Little Egypt): USDA zones 7a, 220–244 frost-free days, in Illinois.
- USDA zones
- 7a
- USDA PHZM 2023, aggregated over the footprint
- Frost-free season
- 220–244 days
- NOAA Regional Climate Centers ACIS, 1991-2020
- Counties
- 11
- US Census TIGER/Line 2025
- Region type
- County cluster
- Growable Ground growing-region registry
Region boundary: Growable Ground growing-region registry — curated county clusters, EPA Level III ecoregions, and town clusters drawn finer than any county. Where a region publishes no measured season, no season figure is shown.
Hardiness Zone Range
What Grows in the Shawnee Hills / Southern Illinois (Little Egypt)
Plants matched to the Shawnee Hills / Southern Illinois (Little Egypt)'s USDA zones 7a, ordered by how much hardiness margin each has across the region — the ones with room to spare at both ends of this band lead. Each links to its full growing profile.
Native Plants of the Shawnee Hills / Southern Illinois (Little Egypt)
Plants the USDA PLANTS Database documents as native and present in this region’s state, kept only where the published hardiness range meets the Shawnee Hills / Southern Illinois (Little Egypt)’s USDA zones 7a — closest range match first. Presence is recorded by state, so a plant can be documented across the state and still be scarce in your corner of the region.
The ground across the Shawnee Hills / Southern Illinois (Little Egypt)
The USDA soil survey maps this ground county by county. These are those records weighted by land area across eleven member counties — this region’s own profile, not a state figure.
The ground is predominantly Alfisols, at 64% of mapped acres, followed by Inceptisols (19%), Entisols (8%) and Mollisols (8%). Five soil orders appear somewhere inside the footprint, which is the honest reason a regional soil answer only goes so far. The most extensive named soils are Hosmer, Menfro, and Grantsburg.
33% of those acres are moderately well drained, and another 31% well drained, 16% somewhat poorly drained. Topsoil pH runs 5.1–6.7 between the lowest and the highest county on record. 19% of the footprint is classed prime farmland.
Soil order
Alfisols
Drainage
Moderately well drained
Topsoil pH
5.1–6.7
Hydric soils
18%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. Alexander County holds the most wetland ground here, at 44% — soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in the Shawnee Hills / Southern Illinois (Little Egypt)
The soil survey reads this ground county by county, and the readings above are those records summed across the Shawnee Hills / Southern Illinois (Little Egypt). Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records33% of the mapped acres across the Shawnee Hills / Southern Illinois (Little Egypt) are moderately well drained — roughly the middle of the drainage range. That is area-weighted across all eleven of its mapped counties.
This is close to the middle most vegetables prefer: it holds enough water to carry a crop between rains without staying waterlogged. The catch is that a wet spring or a low corner can still tip it soggy.
Plant on the site as-is for most crops, but keep the lowest, slowest-draining beds for moisture-tolerant plantings.
USDA NRCS SSURGO
Surface pH
From county recordsTopsoil across the Shawnee Hills / Southern Illinois (Little Egypt) runs pH 5.1–6.7 — near neutral in six of its eleven counties.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Wet ground
From county recordsAbout 18% of the ground across the Shawnee Hills / Southern Illinois (Little Egypt) is mapped as hydric — wetland — soil. Alexander County carries the most, at 44%.
If your lot falls in one of those pockets, a standard in-ground bed will fight waterlogging all season, and roots that need air will struggle.
Check how your own ground drains before you dig; raised beds or moisture-loving plantings turn a wet corner from a problem into a niche.
USDA NRCS SSURGO
Safe to Grow Here?
What the federal record shows across the Shawnee Hills / Southern Illinois (Little Egypt) — and how to grow with it.
Across the Shawnee Hills / Southern Illinois (Little Egypt)'s 11 counties the federal record holds 1,370 documented sites, mostly Underground Storage Tanks (865), Brownfields (270) and Mining (83). The heaviest single county is Williamson County, with 341.
That is a regional count, not a reading of any one lot — proximity to a documented site is information, not a diagnosis. Open the map outlined to the Shawnee Hills / Southern Illinois (Little Egypt) to see which records sit where you actually grow.
Sources Checked
Summed across the 11 counties in the Shawnee Hills / Southern Illinois (Little Egypt)
A note from Gnorman
What an experienced grower watches for around here
In and around the Shawnee Hills / Southern Illinois (Little Egypt), two things run higher than the national average across the 11 counties in the Shawnee Hills / Southern Illinois (Little Egypt) — PFAS (18 sites) and Mining (83 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Your land is one point inside the Shawnee Hills / Southern Illinois (Little Egypt)
Everything above resolves to the Shawnee Hills / Southern Illinois (Little Egypt) as a whole — a footprint spanning USDA zones 7a. Your parcel sits in exactly one of them. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at region scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better regional average.
Your Lot vs the Shawnee Hills / Southern Illinois (Little Egypt) Average
Shawnee Hills / Southern Illinois (Little Egypt) Average
- ●USDA Zones 7a, averaged across Shawnee Hills / Southern Illinois (Little Egypt)
- ●One soil character for all of Shawnee Hills / Southern Illinois (Little Egypt)
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not Shawnee Hills / Southern Illinois (Little Egypt)'s 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in the Shawnee Hills / Southern Illinois (Little Egypt)
Pull a site-specific report for your exact address in the Shawnee Hills / Southern Illinois (Little Egypt) — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that Shawnee Hills / Southern Illinois (Little Egypt) averages can't show:
We read public map data around The Shawnee Hills / Southern Illinois (Little Egypt) — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Shawnee Hills / Southern Illinois (Little Egypt) average
How we know this about the Shawnee Hills / Southern Illinois (Little Egypt)
The boundary: a cluster of neighboring counties. Growing regions have no official boundary, so this footprint is our published one, and every figure on this page was measured over the counties inside it rather than borrowed from the state around it.
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, aggregated across the footprint; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each member’s own record; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above; the soil from the USDA NRCS SSURGO survey, read at each member county’s own record and weighted to this footprint by land area. Where a member carries no record of its own, it is absent from the figure rather than filled in.
Common questions about the Shawnee Hills / Southern Illinois (Little Egypt)
What hardiness zone is the Shawnee Hills / Southern Illinois (Little Egypt)?
The Shawnee Hills / Southern Illinois (Little Egypt) spans USDA hardiness zones 7a, aggregated from the USDA Agricultural Research Service Plant Hardiness Zone Map 2023 across the region's counties. Zones reflect average annual extreme minimum temperatures from 1991–2020 data.
How long is the growing season in the Shawnee Hills / Southern Illinois (Little Egypt)?
Measured between 28°F hard freezes, the Shawnee Hills / Southern Illinois (Little Egypt)'s counties mostly run 224 to 234 frost-free days, median 230 (NOAA Regional Climate Centers ACIS, 1991–2020, over 11 member counties). That 10-day spread is the honest read — no single season describes 11 counties, and each county guide below carries its own.
When does frost risk end in the Shawnee Hills / Southern Illinois (Little Egypt)?
Across the Shawnee Hills / Southern Illinois (Little Egypt), the middle half of member counties see their last 28°F hard freeze between Mar 23 and Mar 28 (median Mar 25), and their first fall freeze between Nov 6 and Nov 12. Those are hard freezes, not the last light frost: tender transplants wait for about Apr 15, and elevation decides which end of a 5-day spread you garden in.
What grows well in the Shawnee Hills / Southern Illinois (Little Egypt)?
The Shawnee Hills / Southern Illinois (Little Egypt)'s conditions suit plants such as Sweet Corn, Tomato, Pumpkin, Apple, Coneflower. What actually thrives on any one site still turns on its specific soil, sun, and drainage — we score each plant against the real conditions at your address.
How is the Shawnee Hills / Southern Illinois (Little Egypt) defined?
The Shawnee Hills / Southern Illinois (Little Egypt) is defined here as a curated cluster of 11 neighboring counties that share a growing character. Growing regions have no official boundary, so this footprint is our published one — every county in it is named on this page.
Which states does the Shawnee Hills / Southern Illinois (Little Egypt) cover?
The Shawnee Hills / Southern Illinois (Little Egypt) spans Illinois. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
Driftless Area and Chicagoland (Chicago metro / lakeshore) share at least one state with the Shawnee Hills / Southern Illinois (Little Egypt). Growing regions overlap and interlock — a single address can sit inside more than one, which is why the precise read is always the parcel, not the region.
What this page reads at the Shawnee Hills / Southern Illinois (Little Egypt)’s own scale
6 of the readings below were taken at the Shawnee Hills / Southern Illinois (Little Egypt)'s own scale — the zone 7a band across its footprint, a median 230-day season across its 11 counties and 1,370 documented federal contamination records across its 11 counties, 341 of them in Williamson County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 7a aggregated across all 11 counties in the footprintUSDA PHZM 2023
- The boundary itself — the 11 counties this region is curated fromGrowable Ground subregion registry
- The growing character that makes this region distinct from the states it crossesGrowable Ground subregion registry
- The 28°F season across the footprint — the middle half of its 11 counties run 224 to 234 frost-free days, median 230NOAA Regional Climate Centers ACIS, 1991-2020
- The federal contamination record over the whole footprint — 1,370 documented federal contamination records across its 11 counties, 341 of them in Williamson County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 64% Alfisols, topsoil pH 5.1–6.7, area-weighted across its 11 mapped countiesUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — its state's curated sets, merged and filtered to zones 7afrom Illinois
What this page can’t tell you
- Which end of the 10-day range your ground sits at — 224 days at one extreme, 234 at the other, decided mostly by elevationfrost dates explained →
- Which of those soils your own ground sits on — the survey maps them county-wide, and they change across a drivewaysoil types explained →
- The soil pH, drainage, sun hours, and frost pockets on one specific lotwhy one lot differs from the next →
Explore the Shawnee Hills / Southern Illinois (Little Egypt)
State growing guides
Counties in this region
Other growing regions across Illinois
An unglaciated landscape of steep ridges, deep valleys, and spring-fed coulees in the Upper Midwest — a stronghold of diversified small farms and cold-hardy fruit.
Chicago's lakeshore and urban core run a full hardiness zone warmer than the collar counties just inland: Cook County sits in zone 6b with about 234 frost-free days, while DuPage, Kane, and McHenry only miles away are zone 5b with roughly 190-200 days. That ~34-day edge — a later fall frost, a buffered spring — comes from Lake Michigan's moderation stacked on the urban heat island, not a named ecoregion, so growers here can push warm-season crops and earlier last-frost dates that an inland-Illinois calendar would flag as risky.