Total production of type I and II Merrill carbines by James H. Merrill of Baltimore, Maryland, was just under 14,500, and nearly all were issued to Union cavalry units including several from New York and Pennsylvania. Merrill was in Washington, D.C. in 1816 and initially worked with his brother William as a gunsmith in Baltimore in the 1840s. His first breech loading design was patented in 1856. This example is a very early type I carbine and has the rarely seen "staple" blade front sight, flush fitting flat lock plate, and lacks government inspection markings. It also features a notch rear sight with two folding leaves marked for 300 and 500 yards, brass patch box and furniture, the early style knurled latch, a sling bar and ring attached to the brass side plate on the left stock flat, matching serial numbers on the tail of the lock and lever, the early style two line marking "J.H. MERRILL BALTO./PAT.JULY, 1858." on the lock below the bolster, and "J.H. MERRILL BALTO./PAT.JULY 1858." on the top of the breech lever.

Fair as heavily cleaned. The iron surfaces are mostly bright gray and have mild pitting throughout. The brass has an aged patina. The stock is very good and has some small dents and a dark oil finish. The markings are mostly crisp, and the action functions fine. These early Merrill carbines are very rarely seen and few likely survived years of hard use during the Civil War. Remaining examples are extremely hard to come by and are missing from most compressive Civil war collections.