State highways in Mississippi are maintained by the Mississippi Department of Transportation. The state numbers its highways in a grid-like pattern, much like the U.S. Route numbering scheme. One and two-digit routes are primary highways. Odd-numbered routes run north–south and start from MS 1, which runs along the Mississippi River, to MS 25, which runs near the Alabama border. In addition to routes 1 through 25, routes 27 through 41 repeat this pattern over the first several routes, still increasing in number from west to east, and routes 43 and higher generally run in the southern part of the state. Even-numbered routes run east–west; these start from MS 2, which runs near the Tennessee state line, and continue to MS 26, which runs in the southern part of the state. With the exception of MS 28, the next several even routes are aligned over routes 2 through 26 in a similar fashion. Exceptions to the numbering scheme There are several state highways that are out of place; they do not fit the numbering scheme: MS 5 runs east of MS 7. MS 22 runs between MS 16 and MS 18. MS 23 runs east of MS 25. MS 27 runs between MS 33 and MS 35. MS 28 runs between MS 18 and MS 24, but it was MS 20 before I-20 was built. MS 29 runs between MS 37 and MS 39. MS 46 runs between MS 32 and MS 42. MS 50 runs between MS 32 and MS 42, but it was MS 10 before I-10 was built (this fit into the grid, between MS 8 and MS 12). MS 67 runs between MS 53 and MS 57, but it was MS 55 before I-55 was built. MS 76 was the number given to the Pontotoc bypass in place of MS 6; this may be the number for the entire Corridor V of the Appalachian Development Highway System The bypass was recently renamed MS 6/US 278 after the completion of the corridor portion that reconnects west of Tupelo. It has since been applied to another section of Corridor V in Itawamba County. Three-digit highways Three-digit highways are organized by their first digit. Routes beginning with a 1 are aborted alignments of U.S. Routes; these include highways 145, 149, 161, 172, 178, 182, 184, and 198. These highways are scattered over their "parent" routes, and have segments beginning and