Maya Rockeymoore Cummings, a policy consultant and chair of the Maryland Democratic Party, will run for the congressional seat vacated by her husband, Representative Elijah E. Cummings, who died last month.

“I am, of course, devastated at the loss of my spouse, but his spirit is with me,” she told The Baltimore Sun on Monday. “I’m going to run this race and I’m going to run it hard, as if he’s still right here by my side.”

Mr. Cummings, who died on Oct. 17 at 68, had represented Baltimore’s Seventh Congressional District for 13 terms beginning in 1996, and rose to become among the House’s most powerful Democrats.

Mr. Cummings was a leading Democrat in the impeachment investigation of President Trump, and his funeral was attended by thousands of mourners, many who praised him as a champion of civil rights and working people.