A new market-rate apartment complex boosts the residential component of Lawrence’s 3.6-million-square-foot Riverwalk mixed-use mill redevelopment up to 255 units.

Officials including Gov. Charlie Baker joined developer Sal Lupoli at a ribbon-cutting ceremony this week for Riverwalk West. The 55-unit complex is marketing studios starting at $1275 per month and two-bedroom, one-bath units ranging from $1,795 to $2,100.

Units feature exposed brick, 16-foot timber ceilings, Carolina pine flooring and kitchens with white quartz countertops. Common area amenities include a rooftop patio, dog run, outdoor fireplace and grill and clubhouse including game room, catering kitchen and fitness center with climbing wall and yoga room.

Since 2004, Lupoli Cos. has attracted more than 200 companies to the once-vacant mill complex on the Merrimack River.

Baker said the complex, located across from the MBTA’s Lawrence commuter rail station, is a model of transit-oriented economic development in Massachusetts Gateway Cities.