Most redistricting discussions focus on the maps, who draws them, what criteria they must meet, and how they will hold up in court. But every redistricting map built from 2030 Census data will ultimately rest on a foundation that GIS and redistricting staff rarely talk about: the Census Bureau’s residential address list. The Local Update of Census Addresses operation is the first to occur in every decennial census cycle, and it gives state, tribal, and local governments their only opportunity to directly help ensure an accurate enumeration by reviewing and submitting updates or corrections to the confidential address list before the census starts. State and local governments use census data to redraw district boundaries for congressional, state legislative, and local bodies, meaning that if the address list undercounts a neighborhood, those residents will be effectively invisible when population totals are tabulated into census blocks, and those census blocks are the building blocks from which every district map is assembled.
The connection between address accuracy and redistricting equity is well-documented in the 2020 cycle. In the Castle Hill neighborhood of New York City, the discovery of nearly 250 previously unlisted housing units, mostly basement apartments and subdivided homes, accounted for more than 10 percent of the area’s total housing stock. In Co-op City, an additional review uncovered more than 300 apartment units not listed in the Census Bureau’s file, many of which were known but geocoded incorrectly. In Issaquah, Washington, a city leveraged a locally developed GIS-based address dataset, originally built for city planning, emergency services, and utility management, to identify and submit nearly 600 additional housing units in the Issaquah Highlands neighborhood that were missing from the Census Bureau’s list. In each of these cases, local GIS staff were the ones who identified the discrepancies because they had local data that the Census Bureau did not. The 2030 LUCA program is designed specifically to capture that local knowledge, and GIS professionals at the county and municipal level are the people best positioned to deliver it.
LUCA Timeline
For GIS and redistricting staff, LUCA preparation that begins now directly serves the redistricting mission in 2031. Although LUCA officially begins in 2027, participating requires groundwork data review, internal planning, and partnership building that local governments can and should start today, including assessing local GIS and data capacity, identifying areas with new development, and understanding which neighborhoods might need corrections. The Census Bureau has made the 2030 LUCA program entirely digital, with web-based tools that eliminate the need to download software, a new address-matching service that allows staff to compare local address files against the Census Bureau’s list, and an extended review window from four to six months. Governments can access Census Address Count Listing Files now, before LUCA officially opens, to begin reviewing how their jurisdiction’s address counts have changed since 2020. For GIS staff who will be doing the heavy lifting on redistricting in 2031, this is one of the highest-value investments they can make in the data quality of the maps they will be asked to defend.
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