Calcasieu Parish was carved from St. Landry Parish by an act of the State Legislature on March 24, 1840. The area had been inhabited by families since about 1815. These families formed settlements along the Calcasieu River. When the parish was formed, the boundaries were: " ...all the territory in the parish of St. Landry, within the following boundaries, to-wit:Commencing at the mouth of the River Mermentau, thence up said river to the mouth of the Bayou Nez Pique, thence up said bayou to the mouth of Cedar Creek, thence due north to the dividing line between the parishes of St. Landry and Rapides, thence along said line to the Sabine River, thence down the said river to the mouth, thence along the sea coast to the place of beginning...." Quoted from the legislative act of formation. The county seat for Calcasieu Parish is Lake Charles, La.
This website is being maintained by Bryant Walker.
I do not live in Louisiana and am unable to help you with local research.
However, you might elect to try the Random Acts of Genealogical Kindness website at http://www.raogk.org. They have volunteers who have offered to help researchers with local research in their respective parishes. Often the work is done for little to no compensation. It's likely you'll find someone in or near Calcasieu Parish that can help you.
If you can't find your information in this parish, it's always wise to investigate the surrounding ones or St. Landry Parish. Keep in mind that during the early years of our country, border changes were frequent. Hopefully, one of these will assist you in your research.