MD 23 begins at an intersection with US 1 (Hickory Bypass) in Hickory. The state highway heads west as two-lane undivided East–West Highway, passing south of a
park and ride lot serving
MTA Maryland commuter buses. MD 23 passes through a commercial area where the highway intersects
US 1 Business (Conowingo Road) and Water Tower Way before the road passes through a narrow forested corridor. The state highway intersects Commerce Road at a
roundabout; Commerce Road heads north into an industrial park surrounding Forest Hill Airport. After crossing over Bynum Run and the
Ma and Pa Trail, a
rail trail along the abandoned right-of-way of the
Maryland and Pennsylvania Railroad, MD 23 intersects
MD 24 (Rocks Road/Rock Spring Road) just south of
Forest Hill. MD 23 continues west through a mix of farmland and forest, passing south of the hamlet of
Fairview and crossing over Phillips Mill Road and Morse Road before East–West Highway reaches its western terminus at MD 165 (Baldwin Mill Road) south of Jarrettsville. MD 23 turns north and joins MD 165 in a concurrency to the center of Jarrettsville. MD 165 continues north as Federal Hill Road and MD 23 turns west onto Norrisville Road; the east leg of the intersection is Jarrettsville Road. MD 23 heads west through farmland and intersects MD 146 (Jarrettsville Pike) and Madonna Road in the village of Madonna. The state highway gradually curves to the north through Shawsville, where MD 23 intersects two highways that head west into
Baltimore County, MD 138 (Troyer Road) and MD 439 (Old York Road). The state highway makes a sharp, curvaceous descent to a crossing of
Deer Creek, next to which is the historic
Ivory Mills complex located east of the road. MD 23 ascends out of the forested creek valley into Norrisville and meets the north end of MD 136 (Harkins Road). The state highway continues north to just south of the Pennsylvania state line. MD 23 turns west and closely parallels the state line for about before the highway veers northwest to cross the border. The highway continues north as PA 24 (Barrens Road) toward the borough of
Stewartstown. MD 23 is a part of the
National Highway System as a principal arterial from US 1 in Hickory west to High Point Road west of Forest Hill. ==History==