The $2.8-billion merger between Brentwood-based Brookdale Senior Living and Seattle’s Emeritus Corp. cements Brookdale’s position as the largest owner and operator of senior living communities in the U.S. The merger between rivals brings the company’s national footprint to 1,100 communities in 46 states.

The Emeritus deal caps almost a decade of large-scale expansion for Brookdale, beginning with its merger of the Frist-founded American Retirement Corp. in 2006. Three years later, Brookdale acquires 21 facilities from Florida-based Sunrise Senior Living Services.