In 1860, the AL&H reached Leesburg in Loudoun County, with plans to extend the line through Hillsborough, Vestal's Gap, Berryville, Winchester and Romney before terminating in (now Keyser, West Virginia), where it would make connections with the Baltimore and Ohio Railroad. Construction may have proceeded pursuant to those plans, as an 1864 Confederate army map shows that the railroad's tracks had passed Leesburg, crossed Catoctin Mountain at Clarke's Gap and passed Hillsborough.