New York State Police has appointed Major Mark A. Nielson of Gardiner, NY, as the 38thtroop commander of Troop K.

Nielson, 51, is replacing Major Katherine Rhode, who is becoming a staff inspector in Albany. Nielson, a Gardiner resident, has been with the state police for 22 years. Officials say he also served as the deputy sheriff of Ulster County.

Troop K covers four counties in the Hudson Valley, including Columbia, Dutchess, Putnam and Westchester.