Islam was not founded by prophet Muhammad (PBUH) or any human. Islam is an Arabic word that means submission to Allah (God in English). In this universal sense, it is Allah command to all His creatures since start of universe creation and even before. As for mankind, Allah left to people the choice of either submitting (or Islam) to Him or denying submitting (Islam) to Him and then on the Day of Judgment they will be either rewarded, forgiven, or punished by the All-Just All-Merciful Allah.
Accordingly, Islam is the religion named and founded by Allah (God in English).
Islam per Quran revelation to prophet Muhammad (PBUH) started by start of God revelation of the first verse of Quran while the prophet was in Mecca (or Maccah), in Saudi Arabia, in year 610 AD through the Angel Gabriel (Jibril) through the revelation of the last verse of Quran in year 632 AD.
Prophet Muhammad.
Hazrat Muhammad (SAW)
Muhammad was not the founder of any branches of Islam. In fact, he was not even the founder of Islam, rather the messenger. As well as this, Muhammad and Islam discourage branches within Islam so it clashes with the question.
madina
This first began in the city of Makkah. There was a prophet named muhammad and he developed the Islam civilization.
mecca
Islam in its present shape originated from Makka Mukarmah, a city situated in Saudi Arabia. Teachings of Islam may be found in the last heavenly book, the holy Qur'an and the sayings of the last Prophet of Islam Hazrat Muhammad (SAW).
Islam is God religion that is created by God. It is not something to be found here or there.
mecca is the place Islam emerged and started and was the city of prophet Muhammad (PBUH)
Prophet Muhammad (PBUH) was born in Mecca. And he didn't found Islam; God did.
Muhammad was the founder of Islam and the proclaimer of the Qurʾān, Islam's sacred scripture.
It was AlMadinah (or Medina) in Saudi Arabia.