Established in 1991 as a small environmental drilling contractor with one rig, Connelly and Associates, Inc. now ranks as one of the largest geotechnical drilling firms in the Washington, D.C. and Baltimore, Maryland region.

Operating in six states and the District of Columbia from offices in Frederick, Maryland, Manassas, Virginia, York, Pennsylvania and Newport, Delaware we send experienced drill crews to perform soil and rock core borings, install monitoring wells or geotechnical instrumentation, or supply other services in support of engineering and environmental consultants. From tripod and track to large truck and ATV- mounted drilling rigs, we have the rig and crew to complete your drilling project safely and on time. Our drillers are licensed, OSHA trained professionals with experience in all types of borehole advancement, including air and mud rotary, wash borings, hollow stem augering and diamond core drilling.

Connelly and Associates, Inc. is a certified contractor by the National Ground Water Association and a participating member of the National Drilling Association.