Momentum for Watertown Square's makeover is growing, as a large multifamily project has been proposed for the Boston suburb's downtown.

Boston-based The Triad Group proposed a 153-unit apartment project at 49-59 Mount Auburn St. on the northeast edge of Watertown Square, according to plans the developer shared at a public meeting Monday night.

The project would be a mix of studio, one-, two- and three-bedroom units.

Triad Group's plans are the third large-scale development proposed near Watertown Square this year.

In September, WSQ Development and Eaglebrook Capital filed plans for a 52-unit apartment building at 108 Water St. That same month, Torrington Properties filed a 40-unit project on a vacant commercial lot at 33 Mount Auburn St.

Triad's proposal is the largest filed under the city's MBTA Communities zoning plan for Watertown's downtown district. The project would include 9,800 SF of retail space.

The project is being proposed as part of the city's Square Area Plan. That plan could ultimately open the door to up to 4,000 housing units, more than double the state's minimum of 1,701 units under the MBTA plan.

Watertown Square's design historically has prioritized cut-through traffic at the expense of greenspace and local business, according to Watertown City Manager George Proakis. In 2024, Watertown's city council and planning board approved zoning changes to transform the square into a mixed-use city center with dense multifamily housing options oriented around walkability and mass transit.

Triad Group has worked on several projects in Massachusetts and across the country, according to its website.

The developer opened its Elm Street Labs project in Watertown last year and sold the 75K SF building to venture capital firm Shannon Life Sciences in July 2024 for $56M.