Indiana Senate District 1, tucked into the furthest northwestern reaches of northwestern Indiana, was represented until January 2022 by Frank Mrvan Jr., at 88 the oldest member of the Indiana Senate and father of the first-term congressman from the area. After missing much of recent legislative sessions due to ill health, Mrvan resigned a few weeks into the 2022 session, creating a vacancy that Democratic party leaders filled with Michael Griffin, the longtime clerk-treasurer of the town of Highland.
Griffin was chosen over Martin Del Rio, a veteran of the war in Iraq and a regional coordinator for the Warrior Care Transition Program. Both are on the ballot for nomination in the May 3 primary.