I-229 begins southeast of Saint Joseph at a directional T interchange with I-29 and US 71 in rural Buchanan County. It heads to the north-northwest and almost immediately meets Route A at a half-diamond interchange; in this case, only southbound I-229 traffic can access Route A and Route A traffic can only access northbound I-229. North of the highway is a housing development while there are fields to the south. Another half-diamond interchange provides access to Route 752. Northbound I-229 traffic may exit to reach westbound Route 752. Full access to Route 752 is provided by the next exit, Route 371, known locally as 22nd Street.