State Sen. Roger Pine, R-Lawrence, has filed to seek re-election.
"It has been an honor to serve the people of my district, and I hope I have earned trust and support enough for another term," said Pine, who is serving in his first four-year term.
State Rep. Tom Holland, D-Baldwin City, has indicated he may challenge Pine for the Senate seat in the November general election.
The district includes part of Douglas County, all of Jefferson County and Leavenworth County, except the cities of Leavenworth and Lansing. It covers the northern third of Lawrence and the communities of Baldwin City, Basehor, Easton, Eudora, Grantville, Linwood, McLouth, Meriden, Nortonville, Oskaloosa, Ozawkie, Perry, Tonganoxie and Valley Falls.
Pine, a farmer, and his wife, Sue, live in the northern outskirts of Lawrence.
In another political announcement Tuesday, state Sen. Vickie Schmidt, R-Topeka, filed to seek re-election to the district that covers southwest Shawnee County.