From the National Soldiers & Sailors Website.
3rd Regiment, Missouri State Militia Cavalry (1st Organization)
Organized at Louisiana, Pike County, Mo., May 5, 1862. Guard line of the North Missouri Railroad and operations in Northeast Missouri against Porter till February, 1863. Prairie Jackson, Mo., April 9, 1862 (Cos. "A," "B" "C"). Near Fayetteville, Ark., July 15. Moore's Mills, near Fulton, July 24. Greenville July 26. Dallas August 24. Newtonia September 13. Monroe County September 16 and October 4. Operations against Marmaduke in Missouri December 31, 1862, to January 25, 1863. Springfield January 8, 1863. Regiment disbanded February 4. 1863.
Regiment lost during service 7 Enlisted men killed and mortally wounded and 3 Officers and 62 Enlisted men by disease. Total 72
3rd Regiment, Missouri State Militia Cavalry (2nd Organization)
Reorganized from 10th Regiment State Militia Cavalry February 2, 1863. Attached to District of St. Louis, Mo., Dept. of Missouri, to June, 1863. District of Southeast Missouri, Dept. of Missouri, to July, 1863. District of St. Louis, Mo., Dept. of Missouri, to July, 1865.
SERVICE.-Moved from Pilot Knob to Patterson, Mo., March 16, 1863. Operations against Marmaduke April 20-May 1, 1863. Patterson April 20. Fredericktown April 22. Castor River, near Bloomfield, April 29. Bloomfield April 29-30. Chalk Bluff, St. Francis River, April 30-May 1. Near Doniphan June 1 (Detachment). Expedition from Cape Girardeau and Pilot Knob to Pocahontas, Ark., August 17-26. Oregon County October 23. Scout from Cape Girardeau to Doniphan and Pocahontas, Ark., October 26-November 12 (Detachment). Scout from Pilot Knob to Doniphan, Ark., October 29-November 5 (Detachment). Reeve's attack on Centreville December 23. Pursuit of Reeves December 23-25. Puliam's December 25. Bolinger County January 14, 1864. Scout from Patterson to Cherokee Bay, Ark., January 20-27 (Detachment). Poplar Bluff February 27. Scout from Pilot Knob to Arkansas line, and skirmishes March 16-25 (Detachment). Oregon County March 19. Wayne County April 26. Scout from Patterson May 6-11 (Co. "A"). Randolph County May 8. Cherokee Bay, Ark., May 8 (Co. "A"). Near St. James June 10. Scout from Patterson to Buffalo July 8-12 (Detachment). Operations in Southeast Missouri and Northeast Arkansas July 18-August 6. Scatterville, Ark., July 28 (Detachment). Osceola August 2. Elkchute August 4. Near Rocheport September 3 (Detachment). Caledonia September 12 (Detachment). Scout in Randolph, Howard and Boone Counties September 15-19 (Detachment). Columbia September 16 (Detachment). Doniphan September 19. Ponder's Mill, Little Black River, September 20. Near Rocheport September 23 (Detachment). Ironton September 26. Shut-in Gap and Arcadia Valley September 26. Fort Davidson, Pilot Knob, September 26-27. Arcadia Valley September 27 (Detachment). Caledonia September 28 (Co. "C"). Leesburg October 1. Ponder's Mills October 3. Moreau Bottom, Jefferson City, October 7. Independence October 22 and 26. Pilot Knob October 26. Leesburg October 28. Duty at Weston, St. Joe, Liberty, Parksville, Pleasant Hill and Lone Jack, operating against guerrillas January to July, 1865. Mustered out July 13, 1865.
Regiment lost during service 4 Officers and 57 Enlisted men killed and mortally wounded and 1 Officer and 102 Enlisted men by disease. Total 164.