The 380,000-member Hotel and Restaurant Employes International Union plans to move its national headquarters from Cincinnati to Washington in April, joining dozens of other unions that have moved here in recent years to enhance their lobbying clout with Congress and federal agencies.

"D.C. is where the action is," said John Kenneally, a union vice president. "We have to keep our fingers on the pulse of Congress to watch out for our members' interests.

"And you can't feel the pulse of the Congress from Cincinnati," he added.

Kenneally said most of the major AFL-CIO-affiliated unions, such as his, have moved here in recent years to keep closer tabs on emerging legislation and regulations that affect members.

Edward T. Hanley, the union's president, has advocated the move here for several years, Kenneally said.

The union, which represents about 10,000 workers in the District, is in the process of buying the former Corcoran School at 28th and M streets NW from the District government for $1.8 million. The union submitted the high bid when the city sought to sell the three-story vacant school in Georgetown in January 1982. The school was built in 1889, vacated in the early 1950s, and subsequently used by the city Department of Transportation.

About 30 Cincinnati-based employes will move here when the office opens.

In addition to renovating the school, Kenneally said, the union plans to have a developer, DRG Inc. of Washington, construct an office building and several town houses on the adjacent land under a leasing agreement designed to defray the purchase cost.