A version of this story appeared in CNN's What Matters newsletter. To get it in your inbox, sign up for free here.
(CNN)The US Census Bureau on Monday announced the winners and losers of the decennial US population count, which you've probably already heard about for the obstacles that got in the way of the 2020 edition. (The short version: the Trump administration tried to game it and Covid delayed it.)
The results will determine which states gain and lose seats in the House of Representatives -- and, as a result, which states gain or lose Electoral College votes, which are allocated based on the number of congressional representatives each state has.
Here's what we learned about who lives in the US right now and where they are:
The US population is growing, but more slowly. As of April 1, 2021, there are 331,449,281 people living in the United States.
That's an increase of 7.4% since 2010, the second slowest growth rate in history, just barely behind the 1940 census after the Great Depression.
The South is booming. Most of the country continues to grow, but the South is growing fastest -- more than 10% since 2010, followed by the Mountain West, the Northeast and the Midwest.
Three states saw negative growth. West Virginia, Illinois and Mississippi all lost population. So did Puerto Rico, which is not a state but has a population of more than 3.2 million Americans.
The balance of power will change in Congress in 2022. Seven of the 435 seats in Congress will be reallocated in 2021.
Texas gains two seats, while Florida, North Carolina, Colorado, Montana and Oregon each gain one.
California, New York, Ohio, Michigan, Pennsylvania, West Virginia and Illinois each lose a seat.
The balance of power in the Electoral College will change in 2024. Each state that gains or loses a congressional seat also gains or loses an Electoral College vote.
Five of the seven new Electoral College votes will go to states won by former President Donald Trump in 2020. Five of the seven votes are leaving states won by President Joe Biden. However, four of the states gaining seats are likely to be competitive in the next presidential election. Three of the states losing seats are also competitive.
Every person counts. The margin between losing a seat and not -- hugely consequential -- is based on complicated math, but can be incredibly slim. The Census bureau suggested a difference of just 89 people meant that New York lost a congressional seat instead of Minnesota.
What are the most and least populous states? California, with more than 39 million residents, is still by far the most populous state. With 52 representatives in Congress, it will have 761,091 people per representative, which is close to the average. Wyoming is the least populous state, with just 576,000 residents.
The country is getting more crowded. Congress is staying the same. In 1960, the first Census for which there were 50 states, there were about 410,481 people in the US per congressperson. That number will have doubled in the decades to come. See the growth at the Census site.
This data is late and likely affected by Covid. The pandemic disrupted the Census just like it disrupted everything else. Most Americans filled out census forms online but the Census workers tasked with going door to door to fill in the gaps had to delay their work because of the pandemic..
This data is part of the fight over citizenship and immigration. The Trump administration tried very hard to include a question about citizenship on the Census form. The concern among many data scientists and Democrats was that the question -- asking people for their citizenship status -- might scare non-citizens from taking part, thus depleting the count. The Supreme Court ultimately killed the citizenship question, but the fight politicized the Census process in a new way. Later, Trump tried to exclude undocumented immigrants from the apportionment data used by the Census bureau, but the President Joe Biden undid that order.
There have been political fights over the Census in the past. There was no reapportionment in 1920 because Congress couldn't agree on how to split up seats without expanding the size of Congress. Nine years later, they passed the Reapportionment Act of 1929, which capped the size of Congress at 435.
Why do we do the Census anyway? The Constitution. Article 1, Section 2 of the Constitution originally stipulated the number of people per representative "shall not exceed one for every thirty Thousand."
That had to change. And so did the people who were counted as part of the Census.
Originally, it read, horribly, that the number of people in the states, "shall be determined by adding to the whole Number of free Persons, including those bound to Service for a Term of Years, and excluding Indians not taxed, three fifths of all other Persons..."
The 14th Amendment forced the government to count everyone as a whole person.
What happens next? More data, then redrawing congressional lines. This is only the first data drop from the Census. More detailed data, including demographics, will be released by September 30. It's that more detailed data that state legislatures or independent commissions will use to re-draw congressional lines within states.
This is a highly political task that some states have tried to depoliticize by placing with nonpartisan commissions.
Others, however, are nakedly partisan. While the Supreme Court has outlawed the drawing of congressional lines around racial data, they have given the green light to draw lines for political reasons. That means Republicans in Texas, for instance, will cram as many Democrats as possible into as few districts as possible, both at the state and federal level.
Democrats will do the same thing in states they control. But Republicans, objectively, have been more successful at gerrymandering.
The political drawing of congressional districts is a key reason they retained control of the House in 2012. It's a large reason they retained control of many state legislatures in 2020.
Multiple states have created nonpartisan or bipartisan commissions to draw congressional lines and they have been shown to yield more competitive congressional races. The Brennan Center for Justice has a roundup of each state's system.
Other states, like Florida, have legislature-approved districts, but there are curbs on gerrymandering written into state law.
Congress could vote to end the practice of gerrymandering. Democrats in the House have endorsed a plan to create independent commissions in every state. But it does not currently have the supermajority needed to cut off debate in the Senate.
