Statistics for occurrence #1 of “Maryland Heights” in chapter 6, page 202 of William Swinton, Campaigns of the Army of the Potomac:

...and (the corps of Reno and Hooker) had the advance by the former. The Confederate defence of Crampton's Pass was left to McLaws, who was engaged in the investment of Harper's Ferry from the side of Maryland Heights ; but Turner's Pass, as commanding the debouche of the main highway from Frederick westward, was committed to the combined commands of Hill and Longstreet. This pass is a deep gorge in the mountains...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Maryland Heights (Maryland, United States) 1,168 36 6 0 0 user votes
Maryland Heights (Missouri, United States) 28 0 0 0 0 user votes
Maryland Heights (Louisiana, United States) 15 0 1 0 0 user votes

† This entity has been selected by the automated classifier as the most likely match in this context. It may or may not be the correct match.