Above: This month, Costco developers took an important step towards bringing a facility to Southborough. (image cropped from site plan)
A year after announcing their intent to bring a Costco to town, developers and the wholesaler have filed the papers for critical hearings in front of the Planning Board.
The hearing will open a week from Monday.
While the opening of the hearing is a critical step, it’s still a long way from project completion. According to a recent update at a Select Board meeting, the wholesaler’s doors aren’t expected to open until late 2027 or early 2028. (And that assumes the Planning Board and Costco will agree on project details.)
In a well-attended Special Town Meeting last fall, voters overwhelmingly approved passing a zoning change written to allow the possibility for the popular discount chain to open a wholesale store (and gas station) at 21 Coslin Drive.
Some voters had questions/concerns, but were assured that passing the zoning did not mean the store had blanket approval. The project would still need a discretionary Special Permit from the Planning Board and Major Site Plan Approval.
Those combined hearings are scheduled to open Monday, September 28, 2026, at 6:50 pm in the Town House Hearing Room and over zoom. The hearing notice states:
This hearing is regarding the redevelopment of 21 Coslin Drive comprised of 26.12 acres ± located in both Southborough in the Industrial Park zoning district and Westborough for a proposed 167,000 SF± Costco wholesale retail warehouse with a 15-pump fueling facility (30 fueling positions) along with new parking, circulation, and loading areas, associated site grading, pedestrian sidewalks and crosswalks, stormwater management features, utility connections, site lighting, and landscaping.
A copy of the application and plans may be viewed at the Planning Office at the Southborough Town House during normal business hours or on the Planning Board Webpage [here]
Project Traffic Analysis & Other Documents
The documents linked from the dedicated page include the one that residents who expressed concerns about potential impacts to roads they live on or frequently travel will most want to see — the Traffic Impact Analysis.
The 329 page report by the applicant’s consultant concluded that “the transportation system can accommodate full build-out of the proposed development” if they mitigate the traffic as recommended:
To address the forecast queues and delay at Route 9 and Crystal Pond Road, we recommend restriping the Crystal Pond Road at Route 9 approach to provide additional defined left turn storage. Signal phase split timings at Route 9 and Crystal Pond Road should also be adjusted to account for anticipated shifts in travel patterns/demands at this intersection. The signal timing adjustments here maintained the same cycle length and general phasing at the existing signal; however, upon realization of the actual traffic volumes in the field, we recommend timings be refined in the field based on observed traffic patterns. We anticipate that a MassDOT access permit will be required for changes to the signal, which will be pursued by the applicant.
Last month, Select Board Chair Kathy Cook updated her board on Costco’s pursuit of changing the traffic light at Crystal Pond. That permitting process wasn’t expected to be completed until February.
At Planning Board’s meeting this week, Town Planner Karina Quinn noted that she believed the traffic topic was what triggered the applicant to submit their “expanded environmental notification” form to the state, which is currently under review. Quinn also told the board that she still needed to get a scope and fee from the board’s peer review engineering consultant. She warned that the “significant” traffic impact analysis report would require more than they are used to seeing for standard reviews.
The other documents also listed as submitted on September 1st as part of “Submission #1” are:
- Cover Letter
- Locus Plan
- Site Plan Set
- Architectural Elevations and Signage Plans
- Hydrogeologic Assessment
- Stormwater Management Report
More Project History
In the summer of 2025, developers pitched to Town officials their plans to convert a section of the old EMC campus behind Route 9 into a site retail location. The property owners (Atlantic Management) were seeking a zoning change to allow a large retailer at 21 Coslin Drive and smaller retail uses on abutting parcels.
Exactly one year ago, I shared the developer’s public reveal that the owners were working with Costco, which was interested in opening a location in the Southborough/Westborough area. The Select Board publicly lobbied for voter support for the project that they hope will be an economic boon.
After the Attorney General’s office approved the zoning change that voters passed at the October Town Meeting, Annual Town Meeting voters approved petitioning the state legislature for a new alcohol license for the project.
This summer, Town Administrator Mark Purple updated the Select Board that the bill filed by Representative Kate Donaghue was replaced in committee with a version that requires the license be assigned within two years. After granted, if it goes dormant and is not re-assigned within three years, it would revert back to the state legislature. (Looking at the bill, it is specified to be used only for the Costco project at 21 Coslin Drive. But, if the Costco project falls through, the bill would allow the board to grant it to a different retailer at the same site.) As of today, it hasn’t been ratified into law yet.
This July, the Zoning Board of Appeals granted relief on zoning setbacks and height restrictions to allow the project as envisioned by the developer. Based on that relief, the applicant was able to move ahead with finalizing their site plans and other materials to submit to the Planning Board.
