| Name of the Candidate | Party Name | Results |
| BASHISHT SINGH | Janata Dal (United) | Won 57018 |
| BIRENDRA KUMAR SINGH | Rashtriya Lok Samta Party | 44111 |
| ALOK KUMAR SINGH | Independent | 27454 |
| MD. SHAMIM SHAH | Bahujan Samaj Party | 23677 |
| RAM DHANI SINGH | Samajwadi Party | 6121 |
| SHASHIKANT TIWARI | Shivsena | 2996 |
| NEERAJ SHUKLA | Independent | 2765 |
| SHIV SHANKAR SINGH | Independent | 2422 |
| PANKAJ KUMAR SINGH | Independent | 1740 |
| MAHENDRA PRASAD GUPTA | Communist Party of India | 1587 |
| DEENANATH PRASAD | Independent | 1387 |
| RUBY DEVI | Rashtra Sewa Dal | 1254 |
| JANAKI BHAGAT | Independent | 1194 |
| RAM AVTAR GUPTA | Janvadi Party(Socialist) | 686 |
| AKHILESH RAI | Manavadhikar Janshakti Party | 602 |
| MD. DILBAS ANSARI | Independent | 565 |
| RAMA PRSAD SINGH | Bahujan Mukti Party | 453 |
| DEV BRAT ARYA | Apna Dal | 227 |
| None of the Above | None of the Above | 1491 |
| AC No | Category | Poll Phases | Last Date of Nominations | Date of Polls | Result |
| 16 | GEN | Phase IV | Oct 7th 2015 | Nov 1st 2015 | Nov 8th 2015 |
Kargahar is a legislative assembly constituency situated in the Rohtas district. It belongs to the Sasaram (SC) Lok Sabha constituency. A total of 2,83,110 people in the Kargahar legislative assembly constituency are eligible to vote under the universal adult franchise. Out of all the voters in the constituency, 1,51,210 are men and 1,31,896 are women. The Kargahar assembly segment consists of Patarhi, Silari, Parari, Dumari and Konar gram panchayats of Sheosagar community development block; Kargahar community development block; and Kochas community development block.
One of the seven assembly segments located in the Rohtas district of Bihar, Kargahar went in favour of the Janata Dal (united) in the last general assembly elections to the state in 2010 when its candidate Ram Dhani Singh won it by defeating his nearest rival Shiv Shankar Singh of the Lok Janashakti Party (LJP ) by a margin of 13197 votes.
In that election, whereas Ram Dhani Singh polled 54190 votes, the LJP nominee received 40993 votes and was followed by Alok Kumar Singh of the Congress who obtained 19552 votes.
Jag Narayan Singh of Mayawati led Bahujan Samaj Party (BSP) was relegated to the fourth place with 11035 votes.
In 2010 the BJP did not field its candidate for the Ekma seat because it was in alliance with the Janata Dal (United) at that time. However, as things stand today, the BJP and the JD (U) have parted ways and the Lok Janashakti Party (LJP), then an ally of the RJD, is now a part of the BJP led NDA, the ruling dispensation at the Centre.
In 2010 the BJP had won 91 seats whereas the JD (U) managed to claim 115 seats, becoming the single largest party. While the RJD put up a dismal performance with only 22 seats, the Congress was able to win only four.
Earlier Ramdhani Singh, Health minister in Bihar government, had emerged victorious from the Dinara assembly seat in Rohtas four times in a row (1990, 1995, 2000 and the February 2005). While his first two wins came as a nominee of the Janata Dal, he won the 2000 and the February 2005 on the ticket of the JD (U).
Kargahar, which came into being before the 2010 assembly polls following the recommendations of the Delimitation Commission, is one of the six assembly segments the combination of which goes on to create the parliamentary constituency of Sasaram which is currently represented by Chhedi Paswan of the BJP who won it by defeating the sitting Congress MP and former Speaker Meira Kumar in 2014 Lok Sabha elections.
Other five assembly segments located in the Lok Sabha constituency of Sasaram are Bhabua, Mohania, Chainpur, Chenari and Sasaram.
Rashtriya Lok Samata Party, an NDA constituent, has fielded Virendra Kushwaha in Kargahar. Angry over denial of ticket, Bihar minister Ramdhani Singh resigned from the cabinet and also quit JD(U). Singh is entering the poll fray from his traditional constituency Kargahar in Rohtas district on a Samajwadi Party ticket. Vashishth Singh of JD(U) has been given ticket from Kargahar Assembly seat in place of Ramdhani Singh. The aggrieved supporters of Ramdhani Singh raised slogans against the CM Nitish Kumar as soon as the list was released and Singh's name was missing from it.