The Arizona State Boundary Lines Amendment, also known as Proposition 3, was on the September 11, 1956 ballot in Arizona as a legislatively-referred constitutional amendment, where it was approved. The measure authorized the legislature to cooperate with any adjoining state to change, alter or redefine any boundary between such state and Arizona, subject to the final approval of the U.S. Congress.
| Arizona Proposition 3 (1956)|
| Yes|| 79,021|| 71.98%|
Election results via: Arizona State Library
Text of measure
The text of the measure can be found here.