This is not a line I'm tracing but saw the Co. Monaghan reference and thought it might help other researchers. (My main Co. Monaghan family is CALVIN of Creevlea near Stonebridge.)
From "HISTORY OF RICHLAND COUNTY, OHIO, INCLUDING THE ORIGINAL BOUNDARIES, ITS PAST AND PRESENT" (etc.) compiled BY A. A. Graham, Mansfield, Ohio: A. A. Graham & Co., Publishers, 1807-1880.
p. 729-730 - BIOGRAPHICAL SKETCHES: City of Mansfield
RITCHIE, JAMES, Sheriff of Richland Co. He was born in the County Monahan, Ireland, Oct. 2, 1843; he came to this county with his parents, who emigrated in 1846. The family afterward returned to Ireland in 1852, and in the latter part of the same year again came to America, when they have since resided. He began carpenter work in 1862 in this city, which trade he acquired and followed until 1875, when he was appointed Deputy Sheriff under John J. Dickson. He was elected Sheriff of Richland Co. in October, 1877, and re-elected in 1879, which position he now holds. He is the youngest man who has ever been elected to that office in this county. He was married in Mansfield to Kate Bell; they are the parents of six children -- Bertie B., born Sept. 19, 1870; Franklin D., born Dec. 8, 1872; William W., born April 4, 1873; Nettie May, born July 29, 1876; James J., born Oct. 13, 1879 ; Kate, April 19, 1880.