One of the nation's largest development firms is reorganizing its U.S. regional leadership upon the planned retirement of one of its executives.

Trammell Crow announced Wednesday Eastern Region President Chris Roth will retire at the end of June after a 41-year career with the Dallas-based real estate firm.

Roth, based in D.C., previously led the firm's Mid-Atlantic business unit, a position now held by Campbell Smith. Roth has worked on several D.C.-area projects, including Sentinel Square, Patriot's Plaza, Market Square and the Shops at Dakota Crossing.

Founded in 1948, Trammell Crow employs more than 550 people in the U.S. and UK. It has developed or acquired 2,700 buildings valued at nearly $65B, with another $10.9B of projects underway and $3.5B in its pipeline.

With Roth's retirement, the firm announced it is shifting its U.S. operating structure from three regions to two.

The markets currently in its Central region, including Dallas, Houston, Chicago and Atlanta, will combine with the Eastern region markets, effective July 1. Adam Saphier, the firm's Central region president, will lead the expanded Eastern region.

The firm is also promoting Managing Director Adam Nims to president of the Western region, effective April 1. He will succeed John Stirek, who will remain with the company and shift to a new role focused on working with the firm's major national occupier clients.

"We carefully planned for these changes and are excited about continuing to see our firm perform at a market-leading level," Trammell Crow CEO Matt Khourie said in a release. "Our growing talent base supports these changes, and will help TCC continue to deliver optimal performance for our clients and capital partners. I know Adam, John and Adam will flourish in their new roles and I am incredibly grateful to the dedication and leadership Chris has given TCC over the past four decades."