The above-named gentleman was born in Champagne County, Ohio, Oct. 7, 1824. His parents emigrated from Baltimore, Md., and settled on a farm near Urbana, Champagne County, Ohio, in 1812. The father of the Doctor died in the year 1829; his mother remained on the "old farm" three years, and removed, in 1832, to West Alexandria, Preble County, where she continued to reside up to the time of her death, which occurred in 1853. Dr. Donnellan is the youngest of a family of ten children, - seven sons and three daughters, - five of whom are now dead. At the age of eighteen he commenced teaching school, and continued this occupation during the winter for several years, pursuing a private course of study during the summer.

In 1848, he commenced the study of medicine in the office of his brother, Dr. N. Donnellan, in West Alexandria. After the completion of his studies, he entered upon the practice of his profession in Farmersville, this County, in April, 1851. He remained there two years; of these two years he cherishes many pleasant recollections. He occupied the same office with H. S. Elliott, Esq., now Judge of the Common Pleas Court. Mr. Elliott had then just commenced the practice of the law. Dr. Donnellan came to Germantown May 3, 1853, having formed a partnership with Dr. C. G. Espich, an old and popular physician, who had been a successful practitioner of medicine in this place from its earliest settlement. This partnership continued until Dr. Espich's death, which occurred Nov. 24, 1853.

Dr. Donnellan was married March 16, 1854, to Mary M. Hiestand, whose parents came to this County at an early day, from Lancaster County, Pa. They have two children, viz., Emma and Annie, who belong to the Reformed Church. The Doctor is a member of the Board of Education in Germantown. He also was a member of the Board of Directors of the Montgomery County Infirmary from 1860 to 1866. He is a member of the Masonic fraternity, and is one of the Charter Members of Germantown Lodge, and was for several years its Master. Dr. Donnellan has been in the constant practice of medicine since 1851, with the exception of a period of four months in 1864, at which time he went out with the National Guardmen, in the 132d Regiment, which did duty at White House Landing, in General Butler's department, near Bermuda Hundred, between the James and Appomattox Rivers, and at Norfolk, Virginia.