Before 1865, where were most of the railroad tracks in the united states concentrated?

North

Explanation:

Before 1865 most of the nation’s rail industries were concentrated in the Northern States because the North was the region of the United States that was more industrialized and also had the biggest concentration of people. The Railroads linked the major cities of the North and also were able to transport goods which made production faster and cheaper.

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there has only been 12 presidents. the 12th president is/was moon jae-in