UPDATED: The shifting map of Congressional districts in New York State: 2005-09 population estimates
NOTE: The maps and analysis below have been superseded by updated maps using official 2010 population counts. Please click here for the new information. Thanks!
The Census Bureau released the first statistics from the 2010 decennial census this week. The nation's population grew by just under 10%, from 281 million to almost 309 million. The Bureau's announcement also included state-by-state population counts, and -- perhaps more importantly -- Congressional apportionment numbers.
Based on the 2010 population, the Bureau has concluded that each Congressional district nationwide will need to have a population of 710,767 people (up from 646,952 in 2000). In New York State, even though our population grew by 2.3% to 19,421,055 people, other states grew faster. Several states will increase their representation in Congress, such as Florida, Georgia, Texas, and Washington. According to the Census Bureau, however, New York will lose two congressional seats, from 29 to 27.
Mapping the current population compared with the NYS target apportionment population
The map below shows how much New York's current districts differ in population size from the apportionment population, and therefore how the state's existing 29 congressional districts may need to change to conform to the 2010 redistricting requirements.
NOTE THAT THE MAP BELOW WAS UPDATED ON 12/23 AS FOLLOWS:
Earlier this week we posted a map that compared the current population estimate for each New York congressional district to the nationwide apportionment population announced by the Census Bureau. The map showed that only one district - 1, on Long Island - had a current population size above the nationwide target population. Several blogs picked up our map, including the State of Politics blog. But a commenter at this blog noted that we shouldn't have used nationwide apportionment number, because dividing New York's population by the nationwide average yields 27.3 Congressional districts. Instead, we needed to divide the state's 2010 population by 27 to obtain the New York State apportionment target population, and then compare each district's population to that.
The corrected map below follows that methodology. New York's population in 2010 was 19,421,055 people, per the Census Bureau's announcement this week. Dividing that number by 27 yields a target population of 719,298 for Congressional districts in New York State. Comparing the current population estimate (for the 2005-09 period) for each NY congressional district yields the map below.
More accurate patterns make a stronger case for upstate losing Congressional seats
Based on the latest local population estimates from the Census Bureau (covering the 2005-09 period), districts shaded yellow are the closest in population size to the target. Districts in red are smaller than the NYS target population by 10% or more. Based solely on population, these districts will need to be combined with others in order to reduce the number of districts in New York to 27.
There are two key differences between the map below and the earlier map we had prepared. One is that the map below shows a starker picture for the Central and Western New York -- existing Congressional districts in those areas are even smaller in population size than we indicated earlier. And the other difference is on Long Island. The earlier map had shaded District 1 in green, indicating its population was above the nationwide apportionment population. But using the NYS target population, District 1's population is slightly below -- only 0.5% less than the target population. Therefore it's no longer shaded in green.
But overall, the patterns are the same -- based solely on district population, the map points to the upstate as the region that will likely need to give up two Congressional seats in the upcoming round of redistricting.
Link to hi-resolution map [PDF].
Here is a link to a spreadsheet listing the district-by-district 2005-09 population estimates and the percent differences from the apportionment population: NYS_Congress_0509 [XLS]
The office of New York State Senator Martin Malavé Dilan has posted several maps and data tables on "demographic trends across New York, including data on Congressional districts, State Senate districts, county population changes as well as prisoner populations from 2000-2009."
This analysis is based on several assumptions that may change. In particular, the population data is based on a 5-year average from 2005 to 2009. The data do not reflect trends, and may differ substantially from the actual population counts based on the 2010 decennial Census. The 2010 decennial population data will be the official data that is used to determine "ideal" district size and eventual redistricting.