Why did the United States experience massive growth in industrialization between 1860 and 1900?

The industrial revolution happened

Explanation:

The US and UK were one of the first ones to industrialize for a reason, they were protected by the sea. They didn't have to take any part in any war and could focus on internal stability. The industrial revolution also introduced a lot of new inventions like the cotton gin, which helped boom America's cotton industry in the south. America is a very rich country in terms such as resources, from the oil in Texas to the steel in Michigan.

abraham lincoln  (february 12, 1809  – april 15, 1865) was an american statesman, politician, and lawyer who served as the 16th  president of the united states  from 1861 until  his assassination  in april 1865. lincoln led the nation through the  american civil war, its bloodiest war and its greatest moral, constitutional, and political crisis.[2][3]  he preserved the  union,  abolished slavery, strengthened the  federal government, and modernized  the u.s. economy.