Getting accurate address data for customers is a challenge on its own, but getting accurate legislative district data add an entirely new level of difficulty on top.
There are a number of reasons why developers might need access to that data however, such as advocacy groups trying to do outreach that involves connecting voters to their representatives.
Melissa provides a number of address lookup services, but in many locations districts cross town boundaries. Two neighbors who live in the same town might be on the district boundary line and belong to two different legislative districts. Therefore, this type of work isn’t as simple as a ZIP code lookup, or even a ZIP+4, which narrows down addresses further to the block or street level.
Melissa’s Cicero API was designed specifically for legislative district data matching, and provides information that is even more accurate than the already specific ZIP+4.
According to Rebecca Womack, product manager for Cicero at Melissa, the service works by converting an address to latitude and longitude and then matching that against shape files that have the exact boundary of the district.
“Some of our competitors only offer matches based on ZIP code or ZIP+4. The Cicero API can do that, too, but the most accurate way to do a match is with a complete address – and that’s where we excel. Legislative districts often don’t adhere to town or ZIP code boundaries. It’s possible that even a ZIP+4 can span two districts,” she said. For example, USPS data claims that all addresses in 12533-7417 belong to the New York’s 17th Congressional District, whereas Cicero’s data shows that only about half of those addresses belong to the 17th District and the other half belong to the 18th District.
Congressional and state legislative districts are redrawn every 10 years following the census to account for changes in population. However, Womack said that “redistricting is becoming increasingly politicized in the U.S. and so districts are changing more frequently – often as a result of litigation.”
“Districts will be drawn and then litigation happens. One group tries to say ‘this is unconstitutional,’ whether it’s at the federal level or at the state level, and then it gets caught up in court and sometimes the districts have to be redrawn,” she explained.
For example, Texas, California, and a number of other states either have or are currently trying to redraw their districts ahead of the 2026 midterm elections.
For anyone building applications that rely on up-to-date district information, staying on top of these changes and ensuring accurate information is key, and this is where the Cicero API can be leveraged.
According to Womack, Melissa stays on top of these changes in real time and is constantly updating its database by acquiring new district boundaries from official sources and then cleaning them to a high resolution to ensure the most accurate address to district matching.
“We’re doing that work for our customers. At the local level, it often entails filing official requests for information, because it’s not just available for download online,” she said.
Besides address matching, the Cicero API also provides elected official profile data, such as social media profiles, websites, photos, and biographies.
“We have over 10,000 current U.S. officials in our database, and while it might seem easy to stay on top of who my local city council members are, when you’re trying to provide accurate information at scale, you really don’t want to track it in-house,” she said. “You would be hiring a team to maintain it and track it, and that just wouldn’t be cost-effective.”
Cost-effectiveness is important to customers and Melissa has taken that into account with its pricing. It utilizes a credit system and varying bucket sizes, so budget-conscious organizations can obtain the smallest bucket, and it scales upwards, with credit discounts for the larger sizes as well.
Similar to the address matching data, the elected officials data is also updated daily. “Officials resign or they pass away, and then we track those vacancies and replacements, whether that’s through an appointment process or special elections. There’s just a lot of moving parts that we are tracking on a daily basis,” she said.
