# Computing Congressional Apportionment

Since that first census in 1790, five methods of apportionment have been used. The current method used, the Method of Equal Proportions, was adopted by congress in 1941 following the census of 1940. This method assigns seats in the House of Representatives according to a "priority" value. The priority value is determined by multiplying the population of a state by a "multiplier."

For example, following Census 2000, each of the 50 states was given one seat out of the current total of 435. The next, or 51st seat, went to the state with the highest priority value and thus became that state's second seat. This continued until all 435 seats had been assigned to a state. This is how it is done.

Equal Proportions Method

P - represents a state's total population

n - represents the number of seats a state would have if it gained a seat (because all states automatically received one seat the next seat gained is "seat two," and the next "seat three," and the next "seat four," and so on.)

The multiplier equals:

Additional Congressional Seats Awarded to Massachusetts using the Equal Proportions Method

 Additional Seat Seat # Priority Value 2 80 4638368.755 3 124 2677963.449 4 172 1893606.115 5 215 1466780.989 6 261 1197621.663 7 311 1012175.044 8 355 876569.301 9 402 773061.4591

Ranking of States for the last Congressional Seat

The US Census Bureau announced on December 21, 2010 that Massachusetts will lose a congressional seat due to re-apportionment based on the 2010 Census.  Minnesota was awarded the 435th seat in Congress.

 Rank State 2010 Population (Military and Overseas included) Members of Congress if awarded the 435th Congressional Seat Additional Population needed to be awarded the last seat 1 Minnesota 5,314,879 8 0 2 North Carolina 9,565,781 14 15,753 3 Missouri 6,011,478 9 15,028 4 New York 19,421,055 28 107,057 5 New Jersey 8,807,501 13 63,276 6 Montana 994,416 2 10,002 7 Louisiana 4,553,962 7 48,858 8 Oregon 3,848,606 6 41,487 9 Ohio 11,568,495 17 144,928 10 Virginia 8,037,736 12 122,192 11 California 37,341,989 54 653,688 12 Illinois 12,864,380 19 270,086 13 Texas 25,268,418 37 652,566 14 Massachusetts 6,559,644 10 178,195

Congressional re-apportionment factors in military and overseas citizens claiming Massachusetts residence.  The Massachusetts in-state resident population of 6,547,629 is used for redistricting.

To learn how Congressional Seats are awarded please visit:  U.S. Census Bureau: Computing Apportionment

## History of Massachusetts Membership in the United States House of Representatives

 Members of Congress from Massachusetts Census Year Members Initial Apportionment 1 1789 8 1st Census 1790 14 2nd Census 1800 17 3rd Census 2 1810 20 4th Census 1820 13 5th Census 1830 12 6th Census 1840 10 7th Census 1850 11 8th Census 1860 10 9th Census 1870 11 10th Census 1880 12 11th Census 1890 13 12th Census 1900 14 13th Census 1910 16 14th Census 3 1920 16 15th Census 1930 15 16th Census 4 1940 14 17th Census 1950 14 18th Census 1960 12 19th Census 1970 12 20th Census 1980 11 21st Census 1990 10 22nd Census 2000 10 23rd Census 2010 9 1. No change was made after the 14th Census (1920), as Congress could not agree on a method for apportionment. 2. Formerly part of Massachusetts, when Maine achieved statehood in 1820, Congress assigned the new state one At-Large Representative, leaving Massachusetts with its allotted 20 Representatives. In the 17th Congress (1821–1823), the final Congress before the apportionment following the 4th Census (1820), Congress reassigned seven Massachusetts Representatives to Maine, leaving Massachusetts with 13 Members of the House. 3. Constitutional Apportionment (Article 1, Section 2). 4. The current method of apportionment began following the 1940 Census