The words of Jeremiah the son of Hilkiah, one of the priests that were in Anathoth in the land of Benjamin; 2 to whom the word of Jehovah occurred in the days of Josiah the son of Amon, the king of Judah, in the thirteenth year of his reigning. 3 And it kept on occurring in the days of Jehoiakim the son of Josiah, the king of Judah, until the completion of the eleventh year of Zedekiah the son of Josiah, the king of Judah, until Jerusalem went into exile in the fifth month.
The start of Jeremiah's preaching is the 13th year of Josiah's kingship. The end of Jeremiah's preaching is the 11th year of Zedekiah's kingship. The number of years from start to end is 41 years.