County: Sullivan County
Location of courthouse: Main St. & 3rd St., Milan
Location of county: North-Central, one county S. of Iowa Border; Crossroads of MO-6 & MO-5, MO-129, MO-139
Organized: Feb. 14, 1845
Named after: James Sullivan of the Revolution and member of Continental Congress
County seat: Milan
Elevation (highest): 981 ft (299 m)
Population: 6,229 (2017)
"In 1812, when Missouri Territory was organized. it contained but five counties: St. Charles, St. Louis, Ste. Genevieve and New Madrid. In 1820, when Missouri was admitted to the Union, the number had increased to fifteen. The new counties organized between 1812 and 1820 were: Washington, in 1812; Howard, in 1816, and Jefferson, Franklin, Wayne, Lincoln, Madison, Montgomery, Pike and Cooper, in 1818. When Missouri became a State, what is now Sullivan County was a part of Howard County, organized as stated above in 1816; but this was previously a part of St. Charles County, organized probably in 1804 or 1805, though its territorial limits were again divided at the second session of the Territorial Legislature, lasting from December 6, 1813, to January 10, 1814. The county then embraced all the territory lying between the Mississippi and Missouri Rivers, extending north indefinitely, and west to the Rocky Mountains. When Howard County was organized January 13, 1816, it included all that part of Missouri Territory north of the Osage River and west of Cedar Creek, and the dividing ridge between the Mississippi and Missouri Rivers. That portion of Howard County lying south of the Missouri River was, in 1818, organized into Cooper County. In 1820, Howard County was reduced to its present size. Out of a small portion of its former limits, Boone County was organized November 16, 1820, and on the same day, out of the territory still remaining, extending from Howard and Boone northward to the present State of Iowa, and westward with the Missouri River to the western boundary of the State, were created the counties of Chartion and Ray, with the Grand River as the dividing line. What is now Sullivan County became a part of Chariton, and so remained until January 6, 1837, when an act was approved organizing the counties of Livingston, Macon, Taney and Linn. According to this act the boundaries of Linn were as follows:
"Beginning at the southeast corner of Township 57, Range 28, west; thence west with same township line to the range line dividing Ranges 21 and 22; thence north with said range line to the township line dividing Townships 60 and 61; thence east with said township line to the range line dividing Ranges 17 and 18; thence south with said range line to the beginning.
"This county was in the act named Linn, in honor of the Hon. Lewis F. Linn, and Section 22 of this act provided that "all that portion of territory lying north of the county of Linn shall be attached to said county for all civil and military purposes, until otherwise provided for by law."
"Thus matters remained until the session of the Legislature of 1842 and 1843, when David Jenkins, a Whig member of the Legislature from Linn County, procured the passage of "An act to define the boundaries of Highland County," the boundary lines being the same as the present boundaries of Sullivan County. But as there was no sufficient population in Highland County to permit a full organization, that county continued to remain attached to Linn for all civil and military purposes. In 1844, by a State census, Highland County was found to contain population sufficient to permit a full organization.
"At the general election that year, both the candidates for the Legislature were from Highland County. E. M. C. Morelock, the Democratic candidate, being successful over Gabriel Jones, the Whig representative, Morelock, succeeded in having passed an act, which was approved February 14, 1845, organizing Sullivan County, with the following boundaries:
"Beginning at the northeast corner of Linn County, where it joins Adair County; thence with the line of Linn County west to the northwest corner of said Linn County; thence due north to the middle of Range 22, with the east line of Grundy County, to the line dividing Townships 64 and 65 to include all of Township 64; thence east with the line of Townships 64 and 65 to the line dividing Ranges 17 and 18, to include all of Range 18; thence due south with said line dividing Ranges 17 and 18 to the place of beginning.
"This county was named Sullivan in honor of Gen. Sullivan, of Revolutionary memory. The name "Highland" was dropped because it had originally been applied in derision, perhaps, of the pretensions of some of the early pioneers.
"On the same day upon which Sullivan County was organized, February 14, 1845, fifteen other counties were organized and by the same act the names of these other counties being Nodaway, Gentry, Lawrence, Harrison, Texas, Mississippi, Hickory, Dunklin, Mercer, Schuyler, Knox, Atchison, Oregon, Moniteau and Cedar. The forty-third section of this act provided that "James Lomax, of Grundy County, Jeremiah Phillips, of Linn County, and William Garritt, Sr., of Macon County, be and they are hereby appointed commissioners to select a permanent seat of justice for the county of Sullivan, and said commissioners shall meet at the house of Armistead Hill, on the first Monday (the 5th) in May next."
"Two weeks later, on February 28, Putnam County was organized with its present southern, eastern and northern boundaries, but its western boundary was the line dividing Ranges 20 and 21; and as Mercer County's eastern boundary was an extension of the eastern boundary of Grundy County, a line extending north and south in the middle of Range 22, there was a tract of country between Putnam and Mercer Counties, reaching from Sullivan County to the Iowa State Line, that was not included in any county. On the 15 of March, 1845, this territory, by an act of the Legislature approved that day, was attached to Sullivan County for civil and military purposes." ~ History of Sullivan County, 1888, Goodspeed, pp. 46, 47, 48.