In 1 Timothy 1:3, in which city did Paul urge Timothy to stay on?

Answer: Ephesus

When Paul left for Macedonia, he urged Timothy to stay on at Ephesus to stop certain men from teaching false doctrines.

“As I urged you on my departure to Macedonia, you should stay on at Ephesus to instruct certain men not to teach false doctrines”— 1 Timothy 1:3 (BSB)