22-year-old Priyanka Kumar, who is physically and mentally challenged, had gone missing on January 26 after she went to attend private computer classes, SSP Yashasvi Yadav said.
Police had registered a case of kidnapping and deputed nine teams to trace the girl.
Priyanka's father, Kidwai Nagar resident Hemnath, is LS Speaker Meira Kumar's cousin, the officer said.
Anwarganj police team today found her while she was de-boarding a Delhi-bound train.
SSP said that Kumar called them to appreciate their efforts in finding the girl.