Alton, IL Noise Levels
Alton, IL: what the federal noise map shows
At Alton, IL, road, rail and aircraft noise all fall below the 45 dB(A) floor BTS's national map can distinguish from silence. This describes Alton as a whole, not a specific block, the underlying BTS map resolves to about 38 meters per pixel, sampled at the town's own center point.
Where Alton ranks
Alton is one of 8,515 places in this dataset with no measurable transportation noise at all, too quiet to rank on loudness. Population is about 24,967, 1,610th largest of the 12,137 places covered here.
Your street may differ from Alton's reading
For a single house or lot in Alton rather than the town-wide figure above, BTS's own map is the same free source, queried directly.
More on how this number was built
For exactly which federal dataset feeds Alton's figure, see the methodology guide. The guide to reading a quiet result explains what "no measurable noise" actually means at Alton.