Kammala wannan jumla: An fara zama a yankin Grajewo na zamani a farkon karni na 15. Bayanan farko da aka ambata daga shekara ta 1426. A ƙarshen karni na 15 ƙauyen karamin cibiyar kasuwanci ne da sana'a. A cikin 1540 garin ya sami haƙƙin birni daga Sarkin Poland Sigismund I Tsoho. A shekara ta 1656, a lokacin
Ruwan Tsufana (yaƙin Poland da Sweden), Yaƙin Prostki ya faru a kusa. Yawan mutanen garin ya ragu sosai sakamakon yakin. A cikin 1692 garin ya mallaki dangin Wilczewski, daga Wilczewo. A cikin 1794 an yi yaƙe-yaƙe na Yakin Kościuszko na Poland kusa da Grajewo. A cikin 1777, garin yana da mazauna 258, kuma a cikin 1800 yana da mazauna 218.