The United States has no complete open list of buildings. The National Address Database is public domain and enormous, but it is fed by the states and counties that choose to contribute, and whole states are absent, which is why it is declared partial and why an American address it does not carry answers exists: null. What the country does publish completely is its streets, with the house-number ranges along them: the Census Bureau's TIGER/Line address-range tables, public domain, one pair of files for each of the 3,227 counties. Since 16 September 2026 Spaw compiles them into a range table that the address lookup consults after a premise register has missed.
The three answers a range can give
A range register answers at two levels of its own, and the lookup reports whichever it reaches.
match_level: range means the street is in the table for that ZIP and the house number falls inside a range published for it. confirmation.house_number reads range, and exists stays null: a range says the number is plausible on that street, not that a building stands there. TIGER ranges are potential ranges — the numbers a segment could carry — so a number inside one might still be a gap between two houses.
match_level: street with the number_out_of_range weight of 20 means the street is in the table for that ZIP and the number falls outside every range published for it. That is the solid negative: 9999 North King Street in Wilmington is not a place, and the table says so.
match_level: none with no weight means the table does not know the street under that ZIP. This is not a denial, and the reason is measured rather than assumed: TIGER assigns ranges to most edges but not all, and a street on a ZIP boundary can carry only its neighbour's ZIP, so a real street can be missing from the ZIP a customer correctly wrote. The table is therefore declared partial, and a street it lacks answers confirmation.street: unconfirmed and costs nothing. Had it been declared complete, a real street would have scored street_not_found one time in some unknown number, and nobody had measured that number.
Where it sits in the order
A range never outranks a building. The National Address Database is consulted first; a building it lists answers premise with the database's coordinates and building facts, and the range table is not asked. Only a NAD miss falls through to TIGER, so an address in a state that contributes to the database gets the stronger answer and an address in one that does not still gets placed on its street.
What was verified
Delaware's three counties were compiled on 16 September 2026: a 4.0-megabyte download, 139,683 ranges on 24,424 streets, a 2.37-megabyte table, 23 seconds to compile, and 2,000 lookups in 0.30 seconds. "500 N King St, Wilmington, DE 19801" answered range, as did "500 North King Street" and "500 King Street"; "9999 N King St" answered street with number_out_of_range; "1209 Orange Street, Wilmington 19801" answered range through the name without its directional; "12 Nonexistent Boulevard" answered none with no signal. Ranges are filed under every name the Census gives an edge, and for a name with a directional also without it, so "Orange St" finds "N Orange St".
Extrapolated from Delaware, the whole country is about 1.6 gigabytes of downloads, some 55 million ranges and a table of about a gigabyte, compiled in a few hours; each county's files are cached so a later run downloads nothing until the Census publishes a new vintage.
How the table is built
Each county publishes two files: the address ranges, one row per side of a street segment with a from-number, a to-number and a ZIP, and the feature names, one row per name a segment carries. Both are database tables inside zip archives, read without unpacking them to disk, and joined on the segment identifier the Census uses for both. A segment with several names — a state route that is also Main Street — is filed under each, and a name with a directional prefix is filed both with and without it, which is how "Orange Street" finds the segment the Census calls "N Orange St". Ranges published backwards are normalised, and the small share of ranges written with hyphens or letters, about six in a thousand in Delaware, are skipped rather than guessed at.
Two limits follow from the source. The weekly round-trip report that checks every premise register against its own file does not measure the range table, because a range is not a row that can be looked up as an address; and a county whose files fail to download fails the whole run, so a partial national table is never installed by accident.
What it is not
A range is not a delivery-point check. Whether the postal service delivers to 500 North King Street is licensed data and stays behind is_deliverable, which answers null until a partner is enabled. A range is the public map's idea of which numbers a street segment could hold, and the answer says exactly that much.