The Loudoun County sheriff and his staff have moved into renovated quarters behind the county jail at Edward Ferry Road and Church Street. The building, a renovated house, holds administrative offices. The criminal investigation division also moved from its substation in Sterling to new quarters on Fort Evans Road. Administrative offices can be reached at 777-2752 or on the Metroline at 471-6050, ext. 406. Call the investigation division at 777-4791 or 478-1086 on the Metroline.

The Sanitation Authority has approved a $31,000 contract to a Manassas firm that will design a 10,000-square-foot building for use by the authority on two acres near the Leesburg Rte. 7 bypass off Sycolin Road. The authority currently leases 3,000 square feet of office space on King Street. A spokesman said the authority will be in its new building by 1987.

The Trapezoid, a band that offers music from the British Isles as well as from America, will perform on the steps of the Old Courthouse in Leesburg Sunday at 7 p.m. Their vocal and instrumental music will include ragtime, jazz, ballads, folk songs and some original compositions. Trapezoid has performed at Wolf Trap, the Smithsonian and on national radio and television. The Bluemont Concert Series, which will sponsor the event, is a community partnership of the town of Leesburg, Loudoun county and the Virginia Commission for the Arts. A Bluemont representative welcomes volunteers and pledges at a reception table on the courthouse lawn every Sunday. For information, call director Peter Dunning at 777-0574.