The Plains of Louisiana is the area north of Baton Rouge (upper East Baton Rouge Parish) most answers to your question can be found by just typing it into the address line of your Program (i.e. Firefox, Explorer or Chrome). There is a rare book that covers the Plains area "The Plains and The People", by Virginia Lobdell Jennings. Pelican Publishing Co., New Orleans, La 1962.
Todd Dulaney todd7034@gmail.com
Great Plains
The address of the Louisiana Area Historical Museum Inc is: 304 Georgia Street, Louisiana, MO 63353-1718
That area code covers the central and northern parts of Louisiana.
Louisiana covers a total of 33,206,400 acres.
It has the 25th largest population on the US.