A Costco is coming to Lake St. Louis. That part of the story is settled: the Board of Aldermen approved it 5-1 on December 15, 2025, and the site sits at Lake Saint Louis Boulevard and Hawk Ridge Circle, right off Interstate 64.
What's less settled is the road.
If you've been watching this corner of the city and trying to figure out what it means for the corridor's near-term future, the headline "Costco approved" tells you less than you'd think. The store's own approval says the road has to be widened first. And if you go looking for confirmation that the widening is locked in, you'll run into a complication almost nobody has laid out clearly: there are two different road projects on Lake Saint Louis Boulevard right now, they share a name, and only one of them is the one Costco is actually waiting on.
The Land Was Worth $9,607. Then It Got Zoned for Retail.
Start with the number that tells you how fast this corridor's value assumptions can shift once a use changes. The 24-acre site Costco is under contract to buy carried a county-assessed market value of $9,607 for 2025, reflecting its prior agricultural designation. That's not a typo. Two parcels totaling 27.43 acres, owned by MRNF Inc. of Chesterfield, sat as farmland-value real estate until a national retailer with a 15-metric site selection system decided the household income and membership density around Lake St. Louis made the location worth building on.
What gets built: a 195,000-square-foot store, roughly 940 parking spaces, a gas station, a tire center, and a separate 25,000-square-foot warehouse section with 21 overhead doors to serve Costco's regional delivery operations. Mayor Brian McKinney has put the expected job count at 175 to 200 new positions. If the store opens, it becomes the retailer's second location in St. Charles County, with the existing St. Peters store about 10 miles and 23 minutes away.
None of that is in dispute. The dispute, such as it is, lives in the traffic numbers.
The Road That Has to Come First
The existing stretch of Lake Saint Louis Boulevard near the site carries an estimated 10,000 vehicles a day already. Costco's own real estate consultants told a neighborhood meeting last October that a store at this location would add roughly 6,000 more, a jump of close to 60 percent on a road that's currently three lanes with shoulders in that segment.
The city's answer was to require the road widen to five lanes, with two new traffic signals and turn lanes, before the store can open. That's not a courtesy, it's a condition of approval. The city also committed to a 14-foot shared-use path along the store's entire frontage and a 6-foot sidewalk tied to a Hawk Ridge Trail extension.
Here's the piece worth sitting with:
The city's pitch has been to widen the road first, let the store open, then lean on the store's own sales tax revenue to help pay for the next round of signals and intersection work down the corridor.
That's a reasonable sequence if the timing holds. It's also a sequence where the store's opening date depends on a construction schedule the retailer doesn't control, and where the longer-term infrastructure spending depends on tax revenue that doesn't exist until the store is already running.
Two Roads, One Name
Here's where it gets easy to get wrong, and where I think the actual information gap sits for anyone trying to read this corridor from the outside.
The road tied to Costco is officially the Lake Saint Louis Boulevard widening project, running from Hawk Ridge Crossing Drive to Route N, expanding from three lanes to five. The city held a public open house on this specific project on February 24, 2026, at Lake Saint Louis City Hall, with a 30-day comment period after.
There is a second, separate project also called Lake Saint Louis Boulevard, this one an extension between Paul Renaud Boulevard and Highway DD, on the opposite side of the city near O'Fallon. It has nothing to do with the Costco site. It has its own controversy: at a St. Charles County Council meeting on November 10, 2025, residents pushed back on the alignment, arguing it would cut through common ground owned by the Preston Woods HOA and complicate drainage near a natural stream. Three weeks later, on December 1, 2025, the County Council voted to strip that project's funding from the 2026-28 Transportation Improvement Plan. A follow-up motion to redirect the money to an unrelated regional project, Highway Inn, failed. The money was pulled but not reassigned, with further budget discussion pushed to a later session.
That's a real funding fight, on a real road, with the same street name as the one Costco needs. If you search for "Lake Saint Louis Boulevard funding" without knowing which segment you're asking about, you can walk away thinking the road tied to your new Costco lost its money in December. It didn't. The widening project near Hawk Ridge kept moving through its own public process into February.
Here's the two side by side:
| Widening (tied to Costco) | Extension (near O'Fallon) | |
|---|---|---|
| Segment | Hawk Ridge Crossing Dr to Route N | Paul Renaud Blvd to Highway DD |
| Change | 3 lanes to 5 lanes | New roadway connection |
| Required before Costco opens | Yes | No |
| Most recent public step | Open house, Feb. 24, 2026 | County funding pulled from TIP, Dec. 1, 2025 |
| Main friction | Timeline vs. store's opening date | HOA and wetlands opposition |
What This Means If You're Watching This Corridor
The store itself is already reshaping the retail mix nearby. Joey B's, a Gianino family restaurant with locations elsewhere in the region, opened its first St. Charles County location this past July on Ronald Reagan Drive, a short drive from the Costco site. The existing Shoppes at Hawk Ridge, anchored by a Walmart Supercenter and a Lowe's, already sits near the proposed store. This pocket of Lake St. Louis was absorbing new commercial tenants before Costco showed up.
If you're comparing Lake St. Louis to other St. Charles County suburbs and this corridor is part of your evaluation, the useful move isn't to ask "is Costco happening." It's happening. The useful question is which road project you're actually checking on, because the two carry very different signals about how fast traffic, noise, and daily driving patterns near Hawk Ridge Circle will change. A widening project that finished its public comment period in the spring and a road extension that just lost its county funding are not the same kind of uncertainty, and treating them as one story will leave you either more worried or more reassured than the facts support.
For anyone weighing a home near this stretch, the practical step is to check the status of the widening project specifically, not the Lake Saint Louis Boulevard name generally, before assuming the traffic picture is settled either way.
FAQ
Is the road required before Costco opens the same project that lost county funding in December? No. The widening required before Costco can open runs from Hawk Ridge Crossing Drive to Route N and had its own public meeting in February 2026. The project that lost Transportation Improvement Plan funding in December is a separate extension near Paul Renaud Boulevard and Highway DD, on a different part of the city.
How much more traffic is the Costco expected to add? Costco's real estate consultants estimated roughly 6,000 additional vehicles a day on a stretch that already carries about 10,000, based on notes from an October 2025 neighborhood meeting.
Will this be the closest Costco to Lake St. Louis? If it opens, it would be the second Costco location in St. Charles County. The existing St. Peters store is currently the closest, about 10 miles and 23 minutes away.
If you're trying to make sense of how a specific street, a specific project, or a specific corridor fits into your search for a home in Lake St. Louis, that's the kind of ground-level reading we do for every client at Reed-Koppel Collective. Get your free home valuation and let's talk about what's actually happening on the block you're watching.
