The membership of the United States House of Representatives changes each decade following the decennial United States Census. Each state receives a number of delegates to Congress based upon its population. This number also determines the number of electors in the presidential elections, which is two more for each state.

Contents

1 House size 2 Apportionment methods 2.1 North Carolina and Utah, 2000 Apportionment 3 State Congressional Delegation Size 3.1 1789-1910 3.2 1920-present 4 Notes 5 See also 6 External links

House size

In 1911, the membership of the U.S. House was set at 433; with the subsequent admission of Arizona and New Mexico as states, membership increased to 435, where it has remained (except for a brief period from 1959 to 1963 following the admission of Alaska and Hawaii, during which House membership was 437).

Apportionment methods

Apart from the fact that the number of delegates is at least one for each state, as required by the Constitution, this number is in principal proportional to population (equalizing the size of congressional districts nationwide). To arrive at whole numbers, the Method of Equal Proportions is used. The method first assigns one seat to each state, and then assigns each additional seat successively to the state with the highest "priority value", a value for the population per seat. For the latter the question would arise whether the current number of seats or one more should be taken. This is solved by taking an intermediate value, the geometric mean of the two. The resulting priority value is the geometric mean of the current population per seat and the population per seat in the case the state gets the extra seat.

Computing for every state and any number of seats the priority value, and sorting the list in descending order of the resulting values, the first 385 are applicable (seats 51-435) (see Census 2000 Ranking of Priority Values (http://www.census.gov/population/censusdata/apportionment/00pvalues.txt)).

The Equal Proportions method has been the fifth distinct method of determining congressional apportionment since the adoption of the United States Constitution. The size of the Congressional delegations from the thirteen original states were assigned by the Constitution for use until the completion of the first U.S. Census. Legislation admitting new states into the union has also designated the number of representatives of states until the time of the next census.

North Carolina and Utah, 2000 Apportionment

Under this method, the 435th seat in Congress granted as a result of the 2000 Census was the 13th granted to North Carolina; the state of Utah failed to obtain a 4th seat by only 857 residents. Utah officials took legal action in an attempt to have this seat reassigned; they contended that the population of Utah was undercounted and that the population of North Carolina was overcounted in several ways:

• The relatively high number of Mormon residents in Utah included over 11,000 who were left uncounted because they were performing missionary work outside the U.S.; North Carolina's figures included a number of overseas military personnel, but they were accurately counted through military channels. Federal law, however only allows for military or government personnel stationed overseas to be counted in the census.
• A higher number of vacation homes in North Carolina meant that census officials who could not contact a home's residents or owners "imputed" more residents than actually existed. The United States Supreme Court ruled (Utah v. Evans) in 2002 that the procedure of imputation was properly applied.
• The Census Bureau admitted to overcounting the student population of a dormitory at the University of North Carolina at Chapel Hill by over 2,000 students; although this was not a large enough error to tip the seat to the Utah delegation, it meant that Utah was, according to revised figures, only about 80 residents short of earning an additional Congressional seat.

A compromise measure was introduced to Congress by Rep. Tom Davis of Virginia, but did not reach a floor vote; it would have temporarily increased the size of Congress to 437 seats until 2010, granting an additional seat to Utah and a voting seat to the District of Columbia.

State Congressional Delegation Size

1789-1910

	1789	1790	1800	1810	1820	1830	1840	1850	1860	1870	1880	1890	1900	1910
Alabama	--	--	--	1	3	5	7	7	6	8	8	9	10	10
Arizona	--	--	--	--	--	--	--	--	--	--	--	--	--	1
Arkansas	--	--	--	--	--	1	1	2	3	4	5	6	7	7
California	--	--	--	--	--	--	2	2	3	4	6	7	8	11
Colorado	--	--	--	--	--	--	--	--	--	1	1	2	3	4
Connecticut	5	7	7	7	6	6	6	4	4	4	4	4	5	5
Delaware	1	1	1	2	1	1	1	1	1	1	1	1	1	1
Florida	--	--	--	--	--	--	1	1	1	2	2	2	3	4
Georgia	3	2	4	6	7	9	8	8	7	9	10	11	11	12
Idaho	--	--	--	--	--	--	--	--	--	--	1	1	1	2
Illinois	--	--	--	1	1	3	7	9	14	19	20	22	25	27
Indiana	--	--	--	1	3	7	10	11	11	13	13	13	13	13
Iowa	--	--	--	--	--	--	1	2	6	9	11	11	11	11
Kansas	--	--	--	--	--	--	--	--	1	3	7	8	8	8
Kentucky	--	2	6	10	12	13	10	10	9	10	11	11	11	11
Louisiana	--	--	--	1	3	3	4	4	5	6	6	6	7	8
Maine	--	--	--	7*	7	8	7	6	5	5	4	4	4	4
Maryland	6	8	9	9	9	8	6	6	5	6	6	6	6	6
Massachusetts	8	14	17	13*	13	12	10	11	10	11	12	13	14	16
Michigan	--	--	--	--	--	1	3	4	6	9	11	12	12	13
Minnesota	--	--	--	--	--	--	--	1	2	3	5	7	9	10
Mississippi	--	--	--	1	1	2	4	5	5	6	7	7	8	8
Missouri	--	--	--	--	1	2	5	7	9	13	14	15	16	16
	1789	1790	1800	1810	1820	1830	1840	1850	1860	1870	1880	1890	1900	1910
Montana	--	--	--	--	--	--	--	--	--	--	1	1	1	2
Nebraska	--	--	--	--	--	--	--	--	1	1	3	6	6	6
Nevada	--	--	--	--	--	--	--	--	1	1	1	1	1	1
New Hampshire	3	4	5	6	6	5	4	3	3	3	2	2	2	2
New Jersey	4	5	6	6	6	6	5	5	5	7	7	8	10	12
New Mexico	--	--	--	--	--	--	--	--	--	--	--	--	--	1
New York	6	10	17	27	34	40	34	33	31	33	34	34	37	43
North Carolina	5	10	12	13	13	13	9	8	7	8	9	9	10	10
North Dakota	--	--	--	--	--	--	--	--	--	--	1	1	2	3
Ohio	--	--	1	6	14	19	21	21	19	20	21	21	21	22
Oklahoma	--	--	--	--	--	--	--	--	--	--	--	--	5	8
Oregon	--	--	--	--	--	--	--	1	1	1	1	2	2	3
Pennsylvania	8	13	18	23	26	28	24	25	24	27	28	30	32	36
Rhode Island	1	2	2	2	2	2	2	2	2	2	2	2	2	3
South Carolina	5	6	8	9	9	9	7	6	4	5	7	7	7	7
South Dakota	--	--	--	--	--	--	--	--	--	--	2	2	2	3
Tennessee	--	1	3	6	9	13	11	10	8	10	10	10	10	10
Texas	--	--	--	--	--	--	2	2	4	6	11	13	16	18
Utah	--	--	--	--	--	--	--	--	--	--	--	1	1	2
Vermont	--	2	4	6	5	5	4	3	3	3	2	2	2	2
Virginia	10	19	22	23	22	21	15	13	11	9**	10	10	10	10
Washington	--	--	--	--	--	--	--	--	--	--	1	2	3	5
West Virginia	--	--	--	-	--	--	--	--	--	3**	4	4	5	6
Wisconsin	--	--	--	--	--	--	2	3	6	8	9	10	11	11
Wyoming	--	--	--	--	--	--	--	--	--	--	1	1	1	1
	1789	1790	1800	1810	1820	1830	1840	1850	1860	1870	1880	1890	1900	1910
U.S. House Total:	65	106	142	186	213	242	232	237	243	293	332	357	391	435

1920-present

See also the list of states ordered by number of electors in the presidential elections, which is two more for each state.

	1920	1930	1940	1950	1960	1970	1980	1990	2000
Alabama	10	9	9	9	8	7	7	7	7
Alaska	--	--	--	1	1	1	1	1	1
Arizona	1	1	2	2	3	4	5	6	8
Arkansas	7	7	7	6	4	4	4	4	4
California	11	20	23	30	38	43	45	52	53
Colorado	4	4	4	4	4	5	6	6	7
Connecticut	5	6	6	6	6	6	6	6	5
Delaware	1	1	1	1	1	1	1	1	1
Florida	4	5	6	8	12	15	19	23	25
Georgia	12	10	10	10	10	10	10	11	13
Hawaii	--	--	--	1	2	2	2	2	2
Idaho	2	2	2	2	2	2	2	2	2
Illinois	27	27	26	25	24	24	22	20	19
Indiana	13	12	11	11	11	11	10	10	9
Iowa	11	9	8	8	7	6	6	5	5
Kansas	8	7	6	6	5	5	5	4	4
Kentucky	11	9	9	8	7	7	7	6	6
Louisiana	8	8	8	8	8	8	8	7	7
Maine	4	3	3	3	2	2	2	2	2
Maryland	6	6	6	7	8	8	8	8	8
Massachusetts	16	15	14	14	12	12	11	10	10
Michigan	13	17	17	18	19	19	18	16	15
Minnesota	10	9	9	9	8	8	8	8	8
Mississippi	8	7	7	6	5	5	5	5	4
Missouri	16	13	13	11	10	10	9	9	9
	1920	1930	1940	1950	1960	1970	1980	1990	2000
Montana	2	2	2	2	2	2	2	1	1
Nebraska	6	5	4	4	3	3	3	3	3
Nevada	1	1	1	1	1	1	2	2	3
New Hampshire	2	2	2	2	2	2	2	2	2
New Jersey	12	14	14	14	15	15	14	13	13
New Mexico	1	1	2	2	2	2	3	3	3
New York	43	45	45	43	41	39	34	31	29
North Carolina	10	11	12	12	11	11	11	12	13
North Dakota	3	2	2	2	2	1	1	1	1
Ohio	22	24	23	23	24	23	21	19	18
Oklahoma	8	9	8	6	6	6	6	6	5
Oregon	3	3	4	4	4	4	5	5	5
Pennsylvania	36	34	33	30	27	25	23	21	19
Rhode Island	3	2	2	2	2	2	2	2	2
South Carolina	7	6	6	6	6	6	6	6	6
South Dakota	3	2	2	2	2	2	1	1	1
Tennessee	10	9	10	9	9	8	9	9	9
Texas	18	21	21	22	23	24	27	30	32
Utah	2	2	2	2	2	2	3	3	3
Vermont	2	1	1	1	1	1	1	1	1
Virginia	10	9	9	10	10	10	10	11	11
Washington	5	6	6	7	7	7	8	9	9
West Virginia	6	6	6	6	5	4	4	3	3
Wisconsin	11	10	10	10	10	9	9	9	8
Wyoming	1	1	1	1	1	1	1	1	1
	1920	1930	1940	1950	1960	1970	1980	1990	2000

Notes

Delegate counts in italics represent temporary counts assigned by Congress until the next decennial census or by the U.S. Constitution in 1789 until the first U.S. Census.

Elections held in the year of a census use the apportionment determined by the previous census.

^* The state of Maine was formed out of portions of Massachusetts in 1820.

^** The state of West Virginia was formed out of portions of Virginia in 1863.

See also

• United States Congress
• United States House of Representatives
• Alabama paradox
• Apportionment paradox

External links

Congressional Apportionment by the U.S. Census Bureau (http://www.census.gov/population/www/censusdata/apportionment.html)

• The Constitution and Paradoxes (http://www.cut-the-knot.org/ctk/Democracy.shtml)
• A Java Simulation of Adams' method (http://www.cut-the-knot.org/Curriculum/SocialScience/Adams.shtml)
• A Java Simulation of Hamilton's method (http://www.cut-the-knot.org/Curriculum/SocialScience/AHamilton.shtml)
• A Java Simulation of the Huntington-Hill method (http://www.cut-the-knot.org/Curriculum/SocialScience/HH.shtml)
• A Java Simulation of Jefferson's method (http://www.cut-the-knot.org/Curriculum/SocialScience/Jefferson.shtml)
• A Java Simulation of Webster's method (http://www.cut-the-knot.org/Curriculum/SocialScience/Webster.shtml)
• History of Apportionment Legislation (http://www.thirty-thousand.org/pages/section_IA1.htm)
• Forty or Thirty Thousand? (http://www.thirty-thousand.org/pages/section_IB1.htm)

• Outcomes of Presidential Elections and the House Size (http://www.thirty-thousand.org/pages/Neubauer-Zeitlin.htm)

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