Des Moines is a city in Iowa.
North/ towards Clear Lake / Minneapolis
Take a city bus up to Ankenny exit 90 on interstate 35, Oralabor Rd. There are many amenities here including several gas stations for people to stop at leaving the city.
There is a lot of traffic here controlled by a 4 way traffic light which gives drivers a very long time to see you before turning on to the interstate.
East/ towards Davenport
Exit 142 on interstate 80 near the suburb of Altoona is well east of town intersecting with state highway 65. There is a Flying J truck stop and several restaurants. Nearby are some nicely wooded areas for camping.
Traffic turning east here is usually moving fast but the road is long enough for drivers to see you at a distance. A large sign is helpful here.
South or West/ towards Kansas City / Council Bluffs
Des Moines is laid out super weird.
West Des Moines on exit 125, Hickman Road, is your best bet going west on Interstate 80 or south on Interstate 35. Here the two Interstates share the same road.
There is a Loves truck stop here and quite a bit of traffic as it is a main street / highway that intersects the two interstates, controlled by a 4 way traffic interchange giving people a chance to see you before proceeding on to the Interstate.
Beware, many law enforcement officials claim that hitchhiking is illegal here, and the Loves Truck stop employees will kick you off their property if they see anyone with a large backpack.
Wait times are some of the worst in Iowa but this spot is your best bet out of town.