Complex sentence: Carter remained in Louisiana after the end of the war and operated a cotton plantation in Bossier Parish in northwestern Lousiana east of the Red River from Shreveport from 1866 until 1871, when financial reverses caused him to abandon the project.
Split into simpler sentences: Carter remained in Louisiana after the end of the war. He operated a cotton plantation in Bossier Parish, located across the Red River from Shreveport, during the period from 1866 until 1871, when financial reverses caused him to abandon the project.