<P> The National Assembly for Wales has 40 constituencies elected by first past the post which are identical to the Welsh constituencies of the House of Commons . Its remaining 20 seats are selected by AMS . </P> <P> The London Assembly has 14 constituencies elected by first past the post, described in the article on London Assembly constituencies . Its remaining 11 seats are also selected by AMS . </P> <P> In the United States, electoral constituencies for the federal House of Representatives are known as congressional districts (of which there are presently 435; the number can be changed but has remained at 435 since 1912, except for a brief period from 1959 - 1962 when two seats were temporarily added for the then - new States of Alaska and Hawaii), while the constituencies for the variously named state legislatures go by a variety of names (and have differing numbers). Long standing practice, reinforced and modified by several U.S. Supreme Court decisions, require the equalization of populations of constituencies after each decennial census, a process known as redistricting . </P> <P> When driven by partisan bodies, this process opens up the possibility of gerrymandering for political or factional advantage . Gerrymandering cannot be used to the disadvantage of any specific racial group (e.g., placing a predominantly African - American community in several districts to dilute the vote would be unconstitutional), but is perfectly legal to dilute the voting strength of the opposing party . </P>

How many electoral districts are there in the us