The Osage County district attorney charged four people with arson after a firefighter said he saw them set fire to Hughes Ranch near Bartlesville.
Deputies said when the firefighter confronted Heather and Stephen Land, and the other two people, on February 9, they ran.
They later told investigators they were trying to put out the fire and ran because they'd been drinking and were scared.
They turned themselves in on Friday.
Deputies are still searching for the two other suspects, Levi Farris and James Tonsing.