In February 2026, Coal City's median home sale price was $299,000, up 18.9% from a year earlier. Only two homes closed that month, down from three in February 2025. By March, the median had fallen to $255,000, down 18.8% year over year. Same village. Same MLS feed. A thirty-point swing in thirty days.
That is not a market correcting itself. That is what happens when a "market" is really two or three houses changing hands, and the sale price of a single acreage listing or a single fully remodeled ranch resets the entire month's headline number. If you are comparing Coal City and Diamond to Morris, Channahon, or anywhere else in Grundy and Will counties, this is the first thing worth knowing before you trust any single median on a portal page.
By August 2026, a broader look at active Coal City listings showed a steadier picture: thirteen homes on the market, averaging around 24 days before going under contract, at an average price near $380,000. That range, from a $255,000 monthly median in March to an average closer to $380,000 five months later, is not proof that values are swinging wildly. It is proof that the sample size here is too small to trend month to month.
So if the median won't tell you where Coal City and Diamond are actually headed, something else will. Two forces are setting the real direction of this market, and neither one shows up in a portal's median line.
The TIF District That Already Filled In Diamond's Front Door
Diamond doesn't have a traditional downtown. What it has instead is the Diamond I-55 Corridor Tax Increment Financing District and the Diamond Enterprise Zone, established by the village as tools to pull commercial development toward Route 113, also known as Division Street. The village's own leadership has been direct about what that's produced. Over roughly the last five years, Diamond has added a newly built Jewel-Osco anchored center, a Starbucks, a Jimmy John's, Diamond Suites, the Morris Hospital Diamond-Coal City Campus, the Diamond Indoor Trap Range, a GasNWash, a Dunkin, and a new Midland States Bank branch. Village updates from 2025 also flagged Hero's West Diamond and a Culver's as slated to open that year.
None of that shows up in a residential median. It shows up in how a Route 113 commute feels, and in what a small commercial parcel near the interchange is worth. Listings currently marketing land in Diamond lean hard on this exact TIF and Enterprise Zone status, and on traffic counts of more than 30,000 vehicles a day along the I-55 frontage. One nearby commercial project, Diamond Point, has been pitching its site by pointing out that the population within a 20-minute drive already tops 60,000, with what its marketing calls a $250 million gap between retail demand and retail supply in the immediate area. Whether or not that exact figure holds, the direction is consistent: Diamond's TIF district is quietly doing what TIF districts are designed to do, and it is doing it along a commercial corridor, not inside a subdivision.
The village has also put more than $4 million into roadway reconstruction on Route 113 itself. That is infrastructure spending aimed squarely at supporting the retail buildout, and it is the kind of investment that raises day-to-day quality of life along that corridor well before it ever shows up as a bump in a home's resale value.
The Bigger Bet Is Zoned Industrial, Not Residential
If Diamond's story is retail and consumer infrastructure, Coal City's is heavier and considerably larger in scale. At the southwest corner of Broadway and Reed Road sits the Inland Rail Park, a 1,470-acre industrial zone that has been listed among Illinois's top-ten megasites by Intersect Illinois, a leading nonprofit economic development organization in the state. The park traces back to 2013, when Clayco and Providence Logistics broke ground on a rail-served development connected to Union Pacific.
That scale dwarfs anything a residential median could register. And it's currently the site of the most consequential, and most contested, development question in either village. Aligned Data Centers has proposed an 11-building hyperscale campus on roughly 300 acres near the intersection of Reed Road and Carbon Hill Road, inside the same industrial-zoned corridor as the Inland Rail Park. According to Coal City's village administrator, Matt Fritz, the village has been in discussions with Aligned since 2024. The project is currently waiting on a Transmission Service Agreement with ComEd for electrical service, and on a Planned Unit Development petition that has not yet been approved.
Aligned held a public open house at Coal City High School in mid-February 2026 to walk residents through the proposal, which the company has described as capable of supporting more than 300 full-time jobs and using a closed-loop cooling system designed to limit daily water draw. The reaction since then has been mixed. An online petition opposing the project has raised concerns about strain on the electrical grid, the effect on residential utility rates, and protection of the local aquifer, and has specifically flagged the campus's proximity to Coal City Middle School and the Early Childhood Center. At the same open house, residents asked directly whether the tax revenue the project could generate would eventually lower their property taxes. Village officials fielded the question but did not commit to a specific answer, since the PUD process, and any tax agreement tied to it, is still unresolved.
Whichever way that PUD petition ultimately goes, it will do more to shape Coal City's industrial tax base and its long-term land economics than any string of individual home sales could. If you are sizing up Coal City against Diamond, or against any other Grundy County town, this is the variable that moves value at scale. A ranch home closing for $299,000 in February tells you almost nothing about it.
What to Actually Watch If You're Comparing These Two Villages
Given all that, here's where the useful signal actually lives if you're weighing Coal City against Diamond right now:
- The pace of the Route 113 corridor buildout in Diamond. Businesses named in the village's own updates, from Culver's to Hero's West Diamond, are the clearest read on how the TIF district is translating into finished, open storefronts versus plans on paper.
- The status of the Aligned Data Centers PUD petition in Coal City. This single approval, whenever it lands, will set precedent for how the rest of the 1,470-acre Inland Rail Park gets built out, and for how much of that industrial tax base ends up benefiting the surrounding residential areas.
- Which side of that line a specific subdivision sits on. Coal City and Diamond share a school district and a border, but they are currently running two different economic experiments. One is a retail-and-services buildout aimed at daily convenience. The other is a heavy-industrial logistics bet aimed at long-term tax base and jobs. A home a mile from the Reed Road corridor and a home a mile from the Jewel-Osco plaza are, in practical terms, exposed to very different futures even if their listing prices look similar today.
A Short FAQ
Does the Aligned Data Center proposal affect homes for sale today? As of August 2026, the project is still in the PUD petition stage, with the Transmission Service Agreement between Aligned and ComEd also pending. No construction has begun, and no tax agreement tied to the project has been finalized.
Is Diamond's TIF district finished? Not entirely. The district has already delivered a Jewel-Osco anchored center and a string of national and local businesses along Route 113, with village updates naming additional openings as recently as 2025. More commercial parcels along the corridor are still being marketed for retail and mixed use.
Why did Coal City's median swing so much in one month? Because the sales volume is small. Two to three closings a month means one property, whether it's a modest ranch or a multi-acre estate, can shift the reported median by double digits without reflecting any broader change in value.
If you're trying to compare a specific street in Coal City against a specific corridor in Diamond, or figure out what a TIF boundary or a pending PUD decision actually means for a parcel you're considering, that's a conversation worth having before you make an offer based on a median you saw online. Hexagon Real Estate works these two villages block by block. Schedule your consultation and we'll walk through the maps, the timelines, and the comps that actually apply to your situation.
