| Country: | JPN |
| Type: | National |
| Route: | 242 |
| Map Custom: | yes |
| Length Km: | 284.9 |
| Length Ref: | [1] |
| Established: | 1 April 1963 |
| Previous Type: | Route |
| Previous Route: | 241 |
| Next Type: | Route |
| Next Route: | 243 |
National Route 242 is a national highway of Japan connecting Abashiri, Hokkaidō and Obihiro, Hokkaidō in Japan, with a total length of 284.9 km (177.03 mi).
Route 242 was originally designated on 18 May 1953 from Kushiro to Nemuro. This was redesignated as Route 44 on 1 April 1963.