The first proposed amendment to the Constitution within the Bill of Rights attempted to set a pattern for growth of the House along with the population, but has not been ratified.
The proposed Wyoming Rule calls for expanding the House until the standard Representative-to-population ratio equals that of the smallest entitled unit (currently the state of Wyoming). This proposal is primarily designed to address the fact that some House districts are currently nearly twice the size of others; for instance, there are nearly 1 million residents in Montana's single district, compared to about 570,000 in Wyoming's. See List of U.S. states by population. It should be noted that, while a larger House size will generally result in the smallest and largest districts being proportionally closer in size, this is not always the case. Therefore in some cases, the Wyoming Rule may actually result in an increase in the ratio of the sizes of the largest and smallest districts. For instance, after the 1990 Census and with a House size of 435, the largest district (Montana's At-large district) had 799,065 residents, 76% larger than the smallest district (Wyoming's At-large district with 453,588 residents). The Wyoming Rule would have given a House size of 547 in 1990. Using that size, the largest district (North Dakota's At-large district) would have had 638,800 residents, 92% larger than the smallest districts (Delaware's two districts at approximately 333,084 residents each), which is larger than the 76% figure mentioned above.
On May 21, 2001, Rep. Alcee Hastings sent a dear colleague letter pointing out that U.S. expansion of its legislature had not kept pace with other countries.
In 2007, during the 110th Congress, Representative Tom Davis introduced a bill in the House of Representatives that would add two seats to the House, one for Utah and one for the District of Columbia. It was passed by the House, but was tripped up by procedural hurdles in Senate and withdrawn from consideration. An identical bill was reintroduced during the 111th Congress. In February 2009 the Senate adopted the measure 61-37. In April 2010, however, House leaders decided to shelve the proposal.