McALLEN — The first major field operation of the 2020 Census begins in the Rio Grande Valley on Sunday.

The U.S. Census Bureau will begin canvassing addresses in McAllen and throughout the RGV to refine its nationwide list of households, according to a news release from the agency.

The list is necessary to deliver invitations to respond to the census and plays a vital role in ensuring a complete and accurate count, the news release said.

Every 10 years, the federal government is tasked with counting every single person living in the United States, regardless of citizenship status. That issue became a major point of contention after the Trump administration tried to include a citizenship question as part of the upcoming decennial count. Hidalgo County joined a slew of other states in a lawsuit to block its addition, with the U.S. Supreme Court ultimately striking it from the forms.

“The Census Bureau is dedicated to ensuring that we are on track, and ready to accomplish the mission of the 2020 Census,” Census Bureau Director Steven Dillingham said in the news release. “We have made many improvements and innovations over the past decade, including better technologies for canvassing neighborhoods and developing complete and updated address listings and maps.”

The bureau created new software called the Block Assessment, Research and Classification Application, or BARCA, which compares satellite images of the United States over time. The software allows the agency to detect new housing developments and keeps costs down.

“We were able to verify 65% of addresses using satellite imagery — a massive accomplishment for us,” said Deirdre Bishop, Census Bureau geography division chief. “In 2010 we had to hire 150,000 people to verify 100% of the addresses in the field, this decade we will only have to hire about 40,000 employees around the nation to verify the remaining 35% of addresses.”

Census employees will begin walking through neighborhoods and checking addresses through mid-October.

The listers will have badges and briefcases indicating their affiliation and will ask a few simple questions to verify the address and any additional living quarters on the property for inclusion in the census.

This operation is one of several conducted for the count, as the agency also partners with the U.S. Postal Service and tribal, state and local officials to update the list.

“Ultimately, the success of the census depends on everyone’s participation,” said Chicago regional director Marilyn Sanders. “And it’s important to remember, when you respond to the census you shape your future and the future of your community.”

Ultimately, the data collected will be used to determine the number of seats each state holds in Congress and how more than $675 billion in federal funds are distributed to states and local communities every year for services and infrastructure, including health care, jobs, schools, roads and businesses.