Saint Clair County

Saint Clair County sits at a gross rent-to-price ratio of 9.0%, which is well above the threshold most investors use to screen for cash-flow viability. The cap rate comes in at 5.85% on a median purchase price of $177,683, which is respectable for an Midwest county at this price point. Price appreciation, however, is a different story: year-over-year home price growth of 1.23% trails inflation, and the appreciation score of 62 out of 100 reflects a market where equity buildup through price appreciation is not the primary return driver. This is a cash-flow-oriented market, not an appreciation play, and investors should underwrite it accordingly. The overall score of 73, landing in the 89th national percentile out of 1,000 counties, tells you this market is genuinely competitive compared to most of the country, even if it carries some real friction points.

The cash-flow score of 90 is among the higher readings you'll see at this price tier, and the affordability index of 92 confirms that entry costs are low enough to matter. At a $177,683 purchase price with 20% down ($35,537), the modeled mortgage payment is $931 at 6.85%, with estimated expenses of $467 per month. That produces a slightly negative cash-on-cash return of -1.91%, or roughly -$65 per month in the base-case model. That gap is narrow enough that a buyer paying slightly below ask, finding a two-unit instead of a single-family, or managing expenses even modestly better than the median estimate can flip this into positive territory. This market suits a disciplined cash-flow buyer who can source deals at or below median, not a passive investor expecting the numbers to work out of the box at list price. Value-add operators will also find the low entry price ($177K median) creates room to force equity with light rehab and push rents above the $1,333 median without needing to be in an appreciating market to make the math work.

The stability score of 50 is the number that deserves the most scrutiny. Half of surveyed markets score better on this dimension, which suggests some exposure to demand cyclicality or population dynamics. Saint Clair County is part of the Metro East area across the river from St. Louis, Missouri, which creates a dual-city dynamic: workers can and do live on the Illinois side to access lower home prices while commuting into St. Louis. That proximity is a meaningful demand anchor that isn't fully captured in a county-level stability score, but it also means rental demand tracks St. Louis employment conditions as much as anything happening inside the county.

The single biggest underwriting consideration here is the property tax rate. Illinois carries a state-average effective property tax rate of 2.27%, which the Tax Foundation flags as very high, and that is not a rounding error, it is a fundamental input to your return model. On a $177,683 asset, that rate produces $4,033 in annual property taxes alone. Combined with $480 in annual insurance, you are looking at $376 per month in tax-and-insurance carry before you pay a dollar of mortgage, maintenance, or vacancy reserve. At 6.85% interest on a 30-year note, that $376 monthly burden represents nearly 40% of your total mortgage payment. Every investor underwriting in Illinois needs this on its own line in the pro forma, not buried in an "expenses" bucket. The caveat worth repeating: 2.27% is a state-average estimate from Tax Foundation 2024 data, and actual county and township millage rates in Saint Clair County may differ, so pull the actual assessor data before closing.

Compared to its neighbors, Saint Clair stands out clearly on the rent-to-price ratio. Its 9.0% gross yield beats Kankakee County (7.4%), Madison County (7.0%), and Williamson County (8.4%). Madison County, the most direct comparison given its geographic adjacency and similar Metro East positioning, has a median home price of $187,237 but a rent of only $1,095, producing a 7.0% gross yield versus Saint Clair's 9.0%. That 200-basis-point yield gap is significant, and it means Saint Clair beats Madison on cash-flow metrics despite being a slightly cheaper market. Williamson County offers the lowest entry price among the neighbors at $152,606, but its rent of $1,067 gives a rent-to-price ratio of 8.4%, still below Saint Clair. Livingston County, at an overall score of 74 (fractionally above Saint Clair's 73) and a median price of $160,375, lacks rent data in this dataset, making direct yield comparison impossible. Choose Saint Clair over these neighbors when your primary objective is gross yield and you have the underwriting discipline to manage Illinois property taxes carefully. Choose a neighbor if you want lower absolute tax exposure or if you have specific sourcing advantages in those markets that offset the yield difference.