Prophet Saleh pbuh was sent to a tribe called Thamud , and it was a great nation from the Arab tribes. They lived in Hijr, which lies between Alsham and alHijaz. It is now called Mada’en Saleh or the town of Ola. In a Hadith about the Tabuk war, it was referred to as Hijr Thamud.
(And to the people of Thamûd We sent their brother Ṣâliḥ. He said, “O my people! Worship Allah—you have no other god except Him.)) Al-Araf. 7: 73
(And to the people of Thamûd We sent their brother Ṣâliḥ. He said, “O my people! Worship Allah. You have no god other than Him. He ˹is the One Who˺ produced you from the earth and settled you on it.)Hud 11:61-62
أرسله الله إلى قبيلة تسمى ثمود، وهي أمة عظيمة من العرب البائدة، وكانت مساكنهم بالحِجر، وهي بين الحجاز والشام. والمكان الذي كانت تسكن فيه تلك القبيلة يسمى اليوم مدائن صالح، أو قرية العلا، وسمي في حديث غزوة تبوك: حجر ثمود.
وَإِلَىٰ ثَمُودَ أَخَاهُمْ صَالِحًا قَالَ يَا قَوْمِ اعْبُدُوا اللَّـهَ مَا لَكُم مِّنْ إِلَـٰهٍ غَيْرُهُ الأعراف 7: 73)
(وَإِلَىٰ ثَمُودَ أَخَاهُمْ صَالِحًا قَالَ يَا قَوْمِ اعْبُدُوا اللَّـهَ مَا لَكُم مِّنْ إِلَـٰهٍ غَيْرُهُ هُوَ أَنشَأَكُم مِّنَ الْأَرْضِ وَاسْتَعْمَرَكُمْ فِيهَا (هود 11: 61-