Update 10:49 p.m.: Incumbent Rep. Roscoe Bartlett has defeated his Republican challengers.

Update 10:48 p.m.: State Sen. Rob Garagiola (D) concedes to banker John Delaney in redrawn House District 6.

Update 10:12 p.m.: Incumbent Democrats John Sarbanes, Donna Edwards, Steny Hoyer, Elijah Cummings, Dutch Ruppersberger and Chris Van Hollen are nominated for House seats.

Update 8:35 p.m.: Sen. Benjamin Cardin wins the Democratic primary.

Update 8:05 p.m.: Mitt Romney wins Maryland primary.

John Delaney, left, who is running for a congressional seat in Maryland's 6th District, greets voter Charles Traylor, of Potomac, Md. at the voting precinct at Robert Frost Middle School on Tuesday. (Ricky Carioti/THE WASHINGTON POST)

Presidential primary: Mitt Romney won the state’s Republican presidential primary, ahead of Rick Santorum, the former senator from Pennsylvania; former House speaker Newt Gingrich; and Rep. Ron Paul (Tex.).

U.S. Sen. Ben Cardin (D-MD). (Pete Marovich/GETTY IMAGES)

Senate: Incumbent Sen. Benjamin L. Cardin (D) won Tuesday’s primary and is favored again in November. He faced a challenge in the Democratic primary from state Sen. C. Anthony Muse (Prince George’s) and seven other Democrats: Raymond Levi Blagmon, JP Cusick, Chris Garner, Ralph Jaffe, C. Anthony Muse, Blaine Taylor, Ed Tinus and Lin Young.

Cardin will face Republican challenger former Secret Service agent Daniel Bongino, who defeated former Defense Department official Richard Douglas in a tight race, along with other candidates Joseph Alexander Danie, Robert "Bro" Broadus, William Thomas Capps, Rick Hoover, David Jones, John B. Kimble, Brian Vaeth and Corrogan R. Vaughn.

House of Representatives:

Updated 10:48 p.m . Senate Majority Leader Robert J. Garagiola (D-Montgomery) was defeated by financier John Delaney in the redrawn 6th Congressional district. The race for the Democratic nomination in the 6th district was the most competitive between the established Annapolis lawmaker and the wealthy newcomer. Other Democratic challengers were Charles Bailey, Ron Little and Milad Pooran.

U.S. Rep. Roscoe Bartlett, R-Md., votes at during Tuesday’s primary election. (Luis M. Alvarez/AP)

In other races:

3rd District: Updated 10:12 p.m. Incumbent John Sarbanes (D) defeated David H. Lockwood. The GOP winner was Eric Delano Knowles, who defeated Armand F. Girard, Thomas E. “Pinkston” Harris and Draper Phelps.

4th District: Updated 10:12 p.m. Democrat Donna F. Edwards defeated fellow Democrats Ian Garner and George McDermott. The GOP winner was Faith M. Loudon, who defeated Randy Gearhard, Greg Holmes and Charles Shepherd.

5th District: Updated 10:12 p.m. Steny Hoyer (D) defeated Cathy Johnson Pendleton (D). On the GOP side, Tony O’Donnell defeated David Hill and Glenn Troy Morton.

8th District: Updated 11:27 p.m. Incumbent Chris Van Hollen defeated fellow Democrat George English. Republicans picked Ken Timmerman, who defeated Gus Alzona, Shelly Skolnick and Dave Wallace.