| Adachi | |
| Native Name Lang: | ja |
| Settlement Type: | Former municipality |
| Seal Type: | Emblem |
| Pushpin Map: | Japan |
| Pushpin Map Caption: | Location in Japan |
| Coordinates: | 37.6073°N 140.4613°W |
| Subdivision Type: | Country |
| Subdivision Name: | Japan |
| Subdivision Type1: | Region |
| Subdivision Name1: | Tohoku Region |
| Subdivision Type2: | Prefecture |
| Subdivision Name2: | Fukushima Prefecture |
| Subdivision Type3: | District |
| Subdivision Name3: | Adachi District |
| Extinct Title: | Merged |
| Extinct Date: | December 1, 2005 (now part of Nihonmatsu) |
| Leader Title: | Mayor |
| Leader Title1: | Vice Mayor |
| Unit Pref: | Metric |
| Area Total Km2: | 44.35 |
| Population Total: | 11,727 |
| Population As Of: | 2003 |
| Timezone1: | JST |
| Utc Offset1: | +09:00 |
| Blank Name Sec1: | City hall address |
was a town located in Adachi District, Fukushima Prefecture, Japan.
On December 1, 2005, Adachi, along with the towns of Iwashiro and Tōwa (all from Adachi District), was merged into the expanded city of Nihonmatsu.
As of 2003, the town had an estimated population of 11,727 and a population density of 264.42 persons per km2. The total area was 44.35 km2.