On the 16th day of November, 1820, the County of Ray was formed. It included all that part of Howard County west of Grand river to the boundary line of the State. All that portion of county north of Ray County to the Iowa line "was attached to the County of Ray for all civil, military and judicial purposes". That act provided that when a division of Ray County should become necessary, the Missouri river should be its southern boundary, the range line between ranges 25 and 26 should be its eastern, the township line between townships 55 and 56 should be its northern, and the range line between ranges 29a nd 30 should be its western boundary. As thus designed Ray County would have included the southern tier of townships in this county.
From the Indian Reservation, and southward to the Missouri river, Ray County was divided into two townships, Bluffton and Fishing River township. Bluffton township included all the land between the Grand river and the range line, separating ranges 29 and 30. Fishing River township included the land situated between the range line, separating ranges 29 and 30, and the western boundary of the state. On the same day, the western portion of Fishing River Township was further sub-divided into Gallatin township. In May 1822, the number of townships was reduced to two - Missouriton and Bluffton. In February 1823, Bluffton and Missouriton townships were sub-divided into three townships: Bluffton township, Crooked River township, and Missouriton township. Bluffton township then included all the land west of range 27, Crooked River township included all the land east of range 28, and Missouriton township included all the land east of 26 (none of which is within the present limits of the county).
In November 1826, Fishing River township was formed, out of the portion of Bluffton township lying west of range 28. It included what is now Polk township and the western part of Camden township, in addition to the land which is currently Fishing River township. It was the portion of land in range 29 north of the Missouri River. In February 1829, the name Bluffton township was changed to Richmond township. Crooked river township boundaries were changed. Missouriton township boundaries were slightly changed. Fishing River township remained the same.
In May 1832, a Marion township was formed out of Richmond township. Marion township is now entirely in Caldwell County. In May 1832, Grand River township was formed. It lay northeast of Marion township and did not contain any land this is in the present day Ray County. June 1825, Shoal Creek township was formed. It lay north of Marion township, and no part of it was in the current Ray County.
By 1836 the territory included in the original limits of the county was reduced to the size of the present day county. Counties originating from Ray County were Clay in 1822, Carroll in 1833, Caldwell in 1836 and Daviess in 1836.