The area was annexed to the Territory of Orleans in 1810, after the short-lived Republic of West Florida capitulated to the United States.

From 1964 to 1984, St. Helena Parish was represented in the Louisiana State Senate by the Democrat businessman W. E. "Bill" Dykes.

In 1983, as a casualty of redistricting, Dykes bowed out of contention in a race which would have pitted him against long-term Senate President Sixty Rayburn of Bogalusa, Louisiana.

[4] In recent years, St. Helena experienced a series of scandals involving parish officials.

[7] He was given an eight-year prison sentence on conviction in 1998 of having placed a political supporter on his assessor office staff; the individual performed no duties.

[9] Ronald "Gun" Ficklin, former mayor of Greensburg, took over the sheriff's office from Phillips in 1998, but on February 5, 2007, Ficklin himself pleaded guilty on multiple counts involving his role in operating "chop shops" — reselling stolen automobiles and parts — using state prisoners to staff these activities and as a pit crew for his race car.

[12] In 2007, Nat Williams was elected as Ficklin's replacement, the first African American to hold the office in that parish.

[14] It is located in the northern tier of the Florida Parishes, and within the Baton Rouge metropolitan area.

[24] St. Helena Parish contains the only identified meteorite impact crater in the state of Louisiana.