In the 1830's and 1840's there were a number of Ohio artists drawing portraits in graphite on paper. Stylistically their work is relatively similar as is its somewhat unusual scale. On average they are about 7 by 9 inches, they are drawn in profile, and the head or head and shoulder crop of the image fills most of the space of the paper. Some of the works contain pastel or paint, although most do not.
This pair of portraits is clearly done by one of the above described artists, I think Robert Seevers, based on details like ear inner contours, profile drawing characteristics, and internal shading of the skin tones.
The main reference on these artists was published in August 2007 in The Magazine Antiques and was written by Arthur and Sybil Kern and Peter and Leslie Warren. It was entitled "Four Ohio Nineteenth century Folk Artists" and a follow-up article by Eleanor Gustafson in February 2008 illustrated others.
Sight size in this pair is 7 1/2 x 9 1/2 inches, and they are, in what appears to be their original mahogany frames, 10 1/2 x 12 1/2 inches. Circa 1825 to 1830.