In the U.S. state of Nebraska, U.S. Highway 34 is a highway which goes between the Colorado border west of Haigler to the Iowa border east of Plattsmouth. Between Culbertson and Hastings, U.S. 34 overlaps U.S. Highway 6. From Grand Island to Lincoln, U.S. 34 has been replaced by Interstate 80 as a high-speed corridor and mostly serves local traffic. On this portion of the highway, U.S. 34 is continuously north of Interstate 80. Within Lincoln, U.S. 34 runs concurrent with all of Interstate 180, and much of it follows O Street.

U.S. Highway 34 begins west of Haigler. At Haigler, it meets Nebraska Highway 27, which connects with K-27 in Kansas. It continues east to Benkelman, where it intersects and overlaps with Nebraska Highway 61 and briefly turns north. After leaving Benkelman, the overlap ends, and U.S. 34 continues northeast through Max and Stratton before meeting Nebraska Highway 25 in Trenton. Before reaching Culbertson, it intersects U.S. Highway 6.

U.S. 34 and U.S. 6 then pass through Culbertson, where they intersect Nebraska Highway 17. They go east together through McCook, where they meet U.S. Highway 83 and briefly overlap. They continue east through Indianola and Bartley, and at Cambridge, intersect the southern segment of Nebraska Highway 47. After passing through Holbrook, they intersect U.S. Highway 283 in Arapahoe.

After Arapahoe, U.S. 34 and U.S. 6 continue east, intersecting U.S. Highway 136, Nebraska Highway 46 and Nebraska Highway 4 before turning northeast. After passing through Atlanta, they meet Nebraska Highway 23 and U.S. Highway 183 in Holdrege. They continue northeasterly through Funk before intersecting and overlapping Nebraska Highway 44 through Axtell. They then continue through Minden, where they intersect Nebraska Highway 10. They continue going northeast through Heartwell, where the road turns due east. At Hastings, U.S. 34 and U.S. 6 intersect U.S. Highway 281, and U.S. 34 then turns north with U.S. 281. U.S. 34 and U.S. 281 then follow a divided highway north to Grand Island, intersecting Interstate 80 south of Grand Island near its crossing of the Platte River. At the south end of Grand Island, U.S. 34 ends its overlap with U.S. 281 and turns east, overlapping the western segment of Nebraska Highway 2.

U.S. 34 and Nebraska Highway 2 continue east through the southern portion of Grand Island, ending their overlap near where they cross the Platte River. It continues east through Aurora and intersecting Nebraska Highway 14 there. It then passes through Hampton and Bradshaw before meeting U.S. Highway 81 in York. After passing through Waco, U.S. 34 then intersects Nebraska Highway 69. It then continues through Utica and Tamora before meeting Nebraska Highway 15 in Seward. U.S. 34 then continues east and becomes a divided highway when it intersects Nebraska Highway 79. It then turns south to go towards downtown Lincoln and intersects Interstate 80 and U.S. Highway 77. It then begins a new overlap with Interstate 180, which overlaps U.S. 34 for its entire length. U.S. 34 then becomes a pair of one-way streets, 9th Street and 10th Street, when Interstate 180 ends. U.S. 34 then turns east on O Street in downtown Lincoln.

U.S. 34 then continues due east from Lincoln, intersecting Nebraska Highway 43 in Eagle. It then intersects Nebraska Highway 63 east of Eagle and then Nebraska Highway 1 near Elmwood. It then intersects Nebraska Highway 50 and Nebraska Highway 67 before passing through Union. It then turns north with U.S. 75, intersects Nebraska Highway 1 again near Murray, and then intersects Nebraska Highway 66 in Plattsmouth. It then passes through Plattsmouth, and enters Iowa at the Plattsmouth Bridge.

Nebraska and Iowa are planning a new U.S. Route 34 bridge which would reroute U.S. 34 north of the Platte River concurrent with U.S. 75, then turn east to cross the Missouri River south of Bellevue, Nebraska. It would then align with the current U.S. 34 alignment near Glenwood, Iowa.