John I Lemigius (died 615) was Exarch of Ravenna (611–615).

John was made Exarch of Ravenna in 611, to replace Smaragdus

Smaragdus

Smaragdus was Exarch of Ravenna twice .During his first tenure, Smaragdus made an alliance with the Franks and Avars against the perennial foes of the Exarchate, the Lombards, and appeared poised to extinguish the Lombard power before it had been fully established...

. He seems to have avoided war with the Lombards

Lombards

The Lombards , also referred to as Longobards, were a Germanic tribe of Scandinavian origin, who from 568 to 774 ruled a Kingdom in Italy...

 throughout his reign. In 615 he was killed with a number of officials. The Liber Pontificalis

Liber Pontificalis

The Liber Pontificalis is a book of biographies of popes from Saint Peter until the 15th century. The original publication of the Liber Pontificalis stopped with Pope Adrian II or Pope Stephen V , but it was later supplemented in a different style until Pope Eugene IV and then Pope Pius II...

mentions that one of the first acts of his successor, Eleutherius

Eleutherius (exarch)

Eleutherius was Exarch of Ravenna . A eunuch, he succeeded John I Lemigius as exarch.Early in his reign, nearly the entire exarchate was unstable. In Ravenna, there was obvious discontent with the Byzantines; in Naples, a certain John of Conza, separated the city from the exarch's control...

, was to kill the persons accused of playing a role in the Exarch John's death.