The byelections were held on November 25.
In Kharagpur Sadar, Trinamool candidate Pradip Sarkar was leading by 11,252 votes after six rounds of counting. Left Front-backed Congress contestant Chittaranjan Mondal, who had surged ahead after the opening round, was now in the third spot.
Kharagpur Sadar in West Midnapore district had elected state BJP president Dilip Ghosh in the 2016 Assembly polls. The constituency went to the hustings after Ghosh got elected to the Lok Sabha from the Midnapore constituency earlier this year.
BJP aspirant Prem Chandra Jha was running second.
The Trinamool has also left behind its opponents in Karimpur, where its nominee Bimalendu Sinha Roy was ahead of his nearest rival state BJP vice president Jay Prakash Majumder by 23,586 votes.
Karimpur constituency in Nadia district had to go for the bypoll as its lawmaker Trinamool's Mahua Moitra won the Lok Sabha battle from Krishnnanagar.
In Kaliaganj, after the fifth round of counting, BJP contestant Kamal Chandra Sarkar was leading by 3,255 votes over his closest rival Tapan Deb Singha of Trinamool Congress.
The seat in North Dinajpur district fell vacant after the incumbent Congress legislator Pramathanath Roy passed away.
The Left Front and the Congress have formed an alliance with the Congress in the fray from Kharagpur and Kaliaganj and Left Front major CPI-M from Karimpur.
The alliance candidates were running third in both Kaliaganj and Karimpur.
During the general elections, the BJP led in the Assembly segments of Kharagpur Sadar and Kaliaganj, while the Trinamool was ahead in Karimpur.
( With inputs from IANS )