The Census Bureau said it will unveil on Monday afternoon which states will gain and lose congressional seats, as part of the first wave of population results from the troubled 2020 decennial count.

The apportionment results, which trigger once-a-decade reshuffling of 435 House seats, will be released following a news conference. Their distribution comes after a nearly four-month delay in the process due to the coronavirus pandemic, numerous natural disasters and other problems with the count. 

Several organizations have projected apportionment results using data from other Census Bureau surveys. Those groups have said they expect states including Texas, Florida, Montana, North Carolina, Colorado, Oregon and Arizona to gain House seats. On the other side, Rhode Island, New York, Pennsylvania, West Virginia, Ohio, Michigan, Illinois, Minnesota or California could lose one or more seats.

Several states and members of Congress have indicated they may challenge the census results in court.

Monday’s release follows months of trouble for the decennial count. The Census Bureau last year missed its statutory Dec. 31 deadline for apportionment results for the first time. On top of that, the agency said it may not deliver the detailed data needed for redistricting until the end of September.

The delays in the data distribution started in March 2020, as the agency suspended many in-person counting efforts due to the coronavirus pandemic. The agency restarted those efforts over the summer, but was then hampered by a record wildfire and hurricane season.

After ending the in-person operations in October, the Census Bureau found issues with hundreds of thousands of records, which it said could take months to fix. On top of that, the agency had to figure out how to count millions of people across the country who had relocated amid the pandemic.

To address concerns over the accuracy of the 2020 tally, the agency said it also plans to release measures of how it counted everyone alongside the apportionment results.

The results to be announced Monday will also include the total U.S. population, which is expected to show the slowest growth in decades. 

Last year, based on data work done separately from the decennial count, the agency estimated between 330 and 335 million people lived in the United States as of April 1, 2020, the reference day for the census. That’s about 20 million more people in the country than in 2010, roughly a 6 percent change. The country’s growth has slowed over the last several decades, last increasing by more than 10 percent between 1980 and 1990.

In addition to the apportionment of House seats, census results are used to draw legislative districts and guide more than $1.5 trillion in federal spending annually.

A bipartisan group of lawmakers in both chambers introduced a bill earlier this month to extend the agency’s deadlines, providing legal cover for the Biden administration plan to deliver final census results as late as September.

Two major court cases are pending over the plan to delay the results; one initiated by Alabama is currently before a three-judge panel and the other from Ohio is before the 6th U.S. Circuit Court of Appeals.