Missouri's 18th Senatorial District is one of 34 districts in the Missouri Senate. The district has been represented by Republican Cindy O'Laughlin since 2019, and she has served as president pro tempore since 2025.

Geography The district is based in rural northeastern Missouri and includes Adair, Audrain, Clark, Knox, Lewis, Macon, Marion, Monroe, Putnam, Ralls, Randolph, Schuyler, Scotland, and Shelby counties. Major municipalities in the district include Hannibal, Kirksville, Mexico, and Moberly. The district is also home to Truman State University, Mark Twain Lake, and several state parks, forests, and conservation areas.

2026 candidates

Democratic primary

Nick Miller, Army combat veteran, business owner, working-class Missourian

Republican primary

Dustin Blue, business owner and Army veteran Sarah Graff, Moberly councilmember and staff member for Congressman Sam Graves Ed Lewis, representative of Missouri House District 6 Gregory Sharpe, representative of Missouri House District 4

Election results (1998–2022) 1998

2002

2006

2010

2014

2018

2022

Statewide election results Year Office Results 2008 President McCain 57.6 – 39.5% 2012 President Romney 64.9 – 35.1% 2016 President Trump 72.4 – 23.4% Senate Blunt 61.6 – 33.8% Governor Greitens 63.1 – 34.3% 2018 Senate Hawley 67.0 – 29.1% 2020 President Trump 74.6 – 23.8% Governor Parson 75.2 – 23.0% Source:

References