| R-21 regional road | ||||
|---|---|---|---|---|
| Regionalni put R-21 | ||||
|   | ||||
| Route information | ||||
| Length | 40 km (25 mi) | |||
| Major junctions | ||||
| East end |  M-2 in Mioska | |||
| West end |  R-20 in Tušina | |||
| Location | ||||
| Country | Montenegro | |||
| Municipalities | Kolašin, Šavnik | |||
| Highway system | ||||
| 
 | ||||
R-21 regional road (Montenegrin : Regionalni put R-21) is a Montenegrin roadway. [1]
This road serves as a shortest connection between Šavnik and Kolašin.
In 1975, a tunnel under the Semolj was started. It would have been 1750 m long, and 420 m were excavated before the work was stopped the same year. [2]
In January 2016, the Ministry of Transport and Maritime Affairs published bylaw on categorisation of state roads. [1] With new categorisation, part of R-18 regional road between Tušina and Mioska was renamed as R-21 regional road.
| Municipality | Location | km | mi | Destinations | Notes | 
|---|---|---|---|---|---|
| Kolašin | Mioska | 0.0 | 0.0 |  M-2  – Kolašin, Podgorica | |
| Šavnik | Semolj | 25.3 | 15.7 | ||
| Boan | 38.9 | 24.2 | No major intersection | ||
| Tušina | 40.0 | 24.9 |  R-20  – Šavnik, Žabljak | ||
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi | |||||
Radovi na toj dionici započeti su daleke 1975. godine i vrlo brzo su prekinuti... Tunel je trebao da bude dugačak 1.750 metara, a ukupno sa obje strane probijeno oko 420 metara.