MD 273 west of Fair Hill was constructed as one of the original state roads starting in the early 1910s.

The highway was reconstructed from east of Rising Sun to the Delaware state line in several stages from the late 1950s to the early 1970s.

MD 273 begins west of Harrisville at a perpendicular intersection with US 1, which heads south as Conowingo Road and north as the Rising Sun Bypass.

The state highway heads south then immediately turns east onto Rising Sun Road.

MD 273 heads east as a two-lane undivided road through the hamlet of Harrisville, where the highway passes the Nathan and Susannah Harris House located on the north side of the road, before meeting MD 276 (Jacob Tome Memorial Highway) at a roundabout.

MD 273 crosses Little North East Creek, intersects Blue Ball Road at a roundabout in Blue Ball Village, and meets Little Elk Creek Road, which leads to Little Elk Farm and the historic home Hopewell.

The state highway passes under three service bridges within the park and parallels an abandoned alignment located north of the road as it crosses Big Elk Creek.

[7][8][9] The gap between Blue Ball and Fair Hill was completed by 1927, the same year US 1 was marked from the Conowingo Bridge through Rising Sun to Sylmar.

[11][12] US 1 bypassed the portion of the state road west of Octoraro Creek when the highway's modern route crossing the Susquehanna River at Conowingo Dam was completed in 1928.

[19][23] The final portion of MD 273 to be reconstructed, from east of Calvert to west of Little Elk Creek, was started in 1972 and completed in 1973.

[24] The highway's roundabout with MD 276 in Harrisville was built in 2002 and 2003, the same years Main Street through Rising Sun underwent a streetscape project.

Construction of the $2.5 million project was originally supposed to begin in March 2016 and be finished in December of that year but was delayed by utility relocations and design errors.