Electoral region (Bulgaria)
The territory of Bulgaria is divided into 31 electoral regions roughly corresponding to the 28 provinces of Bulgaria.
National Assembly Seats
Each electoral region nominates a predefined number of seats to the National Assembly of Bulgaria, according to census data for the population of each region. Since 1991, a proportional electoral system was used, with the exception of 2009 parliamentary election. For 2013 parliamentary election the previous proportional electoral system was restored.In 2009 a mixed system with both simple majority and proportional distribution was introduced. Each one-seat region corresponds to the traditional multi-seat regions. Because of the big diversity of population between regions, this one-seat distribution came into contradiction to article 10 of the Constitution of Bulgaria, stating that elections are to be conducted with equal right to vote. An appeal of this contradiction was brought to the Constitutional Court of Bulgaria, which failed to make a decision, voting 6 to 6. The number of proportional seats for each electoral region was to be reduced by one to allow 31 simple majority seats to be added, while keeping the total number of seats to 240. This led to another controversy, as the seats for some of the regions were reduced by 1, others by 2 and some kept the same number of seats, effectively increasing the total number of seats for the region, including the simple majority seat.
Electoral regions
Most electoral regions correspond to the 28 provinces of Bulgaria, except for the two most populous provinces, which are further subdivided. Plovdiv Province is divided into Electoral region 16, corresponding to Plovdiv municipality and Electoral region 17, covering all other municipalities. Sofia City is divided into Electoral regions 23, 24 and 25. Sofia Province which is distinct from Sofia City is represented by Electoral region 26.| # | Name | Constituencies | 2005 Seats | 2009 Seats | 2013-2017 Seats |
| 1 | Blagoevgrad | Blagoevgrad Province | 10 | 9+1 | 11 |
| 2 | Burgas | Burgas Province | 13 | 11+1 | 14 |
| 3 | Varna | Varna Province | 14 | 12+1 | 15 |
| 4 | Veliko Tarnovo | Veliko Tarnovo Province | 9 | 8+1 | 8 |
| 5 | Vidin | Vidin Province | 4 | 3+1 | 4 |
| 6 | Vratsa | Vratsa Province | 7 | 6+1 | 6 |
| 7 | Gabrovo | Gabrovo Province | 4 | 4+1 | 4 |
| 8 | Dobrich | Dobrich Province | 7 | 6+1 | 6 |
| 9 | Kardzhali | Kardzhali Province | 5 | 4+1 | 5 |
| 10 | Kyustendil | Kyustendil Province | 5 | 4+1 | 4 |
| 11 | Lovech | Lovech Province | 5 | 4+1 | 5 |
| 12 | Montana | Montana Province | 6 | 5+1 | 5 |
| 13 | Pazardzhik | Pazardzhik Province | 9 | 8+1 | 9 |
| 14 | Pernik | Pernik Province | 5 | 4+1 | 4 |
| 15 | Pleven | Pleven Province | 10 | 9+1 | 9 |
| 16 | Plovdiv | Plovdiv municipality | 10 | 9+1 | 11 |
| 17 | Plovdiv | Plovdiv Province, excl. Plovdiv | 11 | 10+1 | 11 |
| 18 | Razgrad | Razgrad Province | 5 | 4+1 | 4 |
| 19 | Ruse | Ruse Province | 8 | 7+1 | 8 |
| 20 | Silistra | Silistra Province | 4 | 4+1 | 4 |
| 21 | Sliven | Sliven Province | 7 | 6+1 | 6 |
| 22 | Smolyan | Smolyan Province | 4 | 4+1 | 4 |
| 23 | Sofia | Vitosha, Sofia Izgrev, Sofia Krasno selo, Sofia Lozenets, Sofia Mladost, Sofia Pancharevo, Sofia Studentski, Sofia Triaditsa, Sofia | 13 | 11+1 | 16 |
| 24 | Sofia | Vazrazhdane, Sofia Iskar, Sofia Kremikovtsi, Sofia Oborishte, Sofia Poduyane, Sofia Serdika, Sofia Slatina, Sofia Sredets, Sofia | 11 | 10+1 | 12 |
| 25 | Sofia | Bankya, Sofia Vrabnitsa, Sofia Ilinden, Sofia Krasna polyana, Sofia Lyulin, Sofia Nadezhda, Sofia Novi Iskar, Sofia Ovcha kupel, Sofia | 12 | 10+1 | 14 |
| 26 | Sofia | Sofia Province | 8 | 7+1 | 8 |
| 27 | Stara Zagora | Stara Zagora Province | 11 | 10+1 | 11 |
| 28 | Targovishte | Targovishte Province | 4 | 4+1 | 4 |
| 29 | Haskovo | Haskovo Province | 8 | 7+1 | 8 |
| 30 | Shumen | Shumen Province | 6 | 5+1 | 6 |
| 31 | Yambol | Yambol Province | 5 | 4+1 | 4 |
Administrative Regions of Sofia
The City of Sofia is divided into 24 Administrative regions. Electoral regions 23, 24 and 25 cover 8 Administrative regions each.| # | Administrative Region | Electoral Region |
| 1 | Bankya | 25 |
| 2 | Vitosha | 23 |
| 3 | Vrabnitsa | 25 |
| 4 | Vazrazhdane | 24 |
| 5 | Izgrev | 23 |
| 6 | Ilinden | 25 |
| 7 | Iskar | 24 |
| 8 | Krasna polyana | 25 |
| 9 | Krasno selo | 23 |
| 10 | Kremikovtsi | 24 |
| 11 | Lozenets | 23 |
| 12 | Lyulin | 25 |
| 13 | Mladost | 23 |
| 14 | Nadezhda | 25 |
| 15 | Novi Iskar | 25 |
| 16 | Ovcha kupel | 25 |
| 17 | Oborishte | 24 |
| 18 | Pancharevo | 23 |
| 19 | Poduyane | 24 |
| 20 | Serdika | 24 |
| 21 | Slatina | 24 |
| 22 | Studentski | 23 |
| 23 | Sredets | 24 |
| 24 | Triaditsa | 23 |