Boston Private Financial Holdings Inc. said Monday that it is selling its branches in Washington state to Sterling Financial Corp., of Spokane, Wash., the parent of Sterling Savings Bank.

The deal marks the second time in several years Boston Private, the parent of Boston Private Bank & Trust Co., has pulled out of one of its major markets. Boston Private sold its troubled Florida unit, ­Gibraltar Private Bank & Trust, in 2009.

The sale, due to close in the first half of next year, involves three locations, in ­Seattle, Bellevue, and Redmond, Wash., that have a combined $190 million in deposits and $270 million in gross loans. A sale price is expected to be announced later.

Boston Private Holdings’ chief executive, Clayton G. Deutsch, said the deal will ­allow it to focus its private banking operations in New England, the San Francisco Bay Area, and Southern California.

“This lets us concentrate our resources,” Deutsch said. He said the company had too small a position in the Pacific Northwest.

Boston Private Holdings is a holding company with private banking, investment management, and wealth advisory operations.