Conquests During his Khilafat
I will mention the conquests during the Khilafat of Hazrat Uthman (ra). During the Khilafat of Hazrat Uthman (ra), Allah the Almighty granted victory to the Muslims in the following areas: conquest of Ifriqiya, i.e. the areas of Algeria and Morocco, conquest of Al-Andalus, Spain in 27 AH, conquest of Cyprus in 28 AH, conquest of Tabaristan in 30 AH, conquest of Al-Sawari [Battle of the Masts], conquest of Armenia, conquest of Khorasan in 31 AH, expeditions towards Byzantine territories, conquests of Marw Al-Rudh, Taleqan, Faryab, Jowzjan, Tokharistan, Balkh and Herat in 32 AH. Aside from this, it is mentioned that Islam entered India during the reign of Hazrat Uthman (ra).
(Sheikh Shah Moinuddin Ahmad Nadvi, Siyar al-Sahabah, Vol. 1 [Karachi, Pakistan: Dar al-Isha‘ah, 2004], pp. 165-168) (Ibn Kathir, Al-Bidayah wa al-Nihayah, Vol. 10, Year 31, [Beirut, Lebanon: Dar al-Kutub al-Ilmiyyah, 1998] p. 237) (Muhammad Ibn Jarir al-Tabari, Tarikh al-Tabari, Vol. 2, p. 625, year 31, Dar al-Kutub al-Ilmiyyah, Beirut, 1987) (Bar-e-Saghir mein Islam ky Awwalin Nuqush, Muhammad Ishaq Bhatti, Research Institute, pp. 63, 65)