Transcontinental Development Corp. of Santa Barbara, Calif., sold 274 lots at Ocean Pines, a resort community just west of Ocean City, Md., at auction last Saturday for a total of $2.3 million. Nine hundred bidders were on the scene to purchase lots for $3,000 to $28,000, said Stewart Hawkins of Kennedy-Wilson Inc., a real estate marketing firm in Santa Monica, Calif., which conducted the auction.

Deborah A. Moxley, who works for J. Vernon Hall Inc. in Fork, Md., has been chosen as Realtor associate-of-the-year by the Maryland Association of Realtors.

Shuter's Hill, a cluster of 35 town houses, has been started by Sonny DeCesaris & Sons Builders Inc. near the George Washington Masonic Memorial on Roberts Lane in Alexandria. Golubin & Warwick Inc. is handling sales of the two- and three-bedroom brick dwellings, which will be priced from $120,500.

The Veterans Administration has named Robert O'Toole deputy director of the loan guaranty service of the VA national mortgage office here. O'Toole joined VA in 1963 and recently served as loan guaranty officer of the regional office serving this area.

The average household size in Fairfax County has declined from 3.51 persons 10 years ago to about 2.88 in 1980, a new county survey shows. The decline was attributed to lower birth rates and a growing proportion of single-person households. Fairfax's current estimated population of 600,300 is 2.2 percent lower than a projection made a year ago, the county said.

William R. Deven has been named corporate planning vice president of the Ryland Group Inc., a Columbia-based national home building firm. Deven previously was a vice president of the firm in Cincinnati.

James B. Warkentin, a realty broker in Springfield, has received the Frank Homes memorial "exchangor of the year award" from the Metropolitan Washington Real Estate Exchangors. The group's members specialize in exchanges of properties rather than conventional transactions.

The eight-story GTE-Telenet Building is nearing completion at Tysons Corner. Designed by Arthur Cotton Moore Associates, the 150,000-square-foot building is made of steel, precast concrete and glass and has a curving facade on the upper floors. GTE-Telenet will move there in September.

Louis H. Nevins has been named senior vice president and director of the Washington office of the National Association of Mutual Savings Banks. He has been with the association since 1971. James J. Butera was named vice president and associate director of the Washington office.

KLM Limited Partnership has sold 113,019 square feet of land in the Flint Hill Office Park in Oakton for $745,885 to Engineering-Science Inc., of Arcadia, Calif., Walker & Dunlop reported. The new owner plans to build a headquarters building for its eastern region.

Alex. Brown Realty Inc., a firm specializing in syndication of investments in real estate in six states, has opened an office in Easton, Md. William Hough is the manager.

Barbara Paige has been named sales manager of Fran Smith & Associates in Dale City and David Shore, sales manager of Landmark Properties in Winchester, Va., Red Carpet Real Estate announced.

Chris Martin, a member of the Northern Virginia Board of Realtors, was honored recently by the Arlington County Fair Housing Board for work as chairman of the equal opportunity and housing committee of the Realtor board.

The Washington-based Solar Energy Industries Association recently gave special awards to Sens. Robert Packwood (R-Ore.) and John Durkin (D-N.H.) for their efforts on behalf of solar. The association represents most of the producers of solar products in the United States.