Response: I’tikaaf is for a person to confine himself to the masjid in obedience to Allaah (Subhaanahu wa Ta’aala) so as to separate himself from the people and free himself (from the chores of daily life) to exert himself in worshipping Allaah. This can take place in any masjid, whether it is a masjid in which people gather for the Jumu’ah prayer or not. However, it is better (to perform the i’tikaaf) in a masjid in which the people gather for the Jumu’ah prayer so that one performing i’tikaaf is not forced to leave the masjid (in which he is doing i’tikaaf) to go to anothermasjid for the Jumu’ah prayer.
Shaykh Ibn ‘Uthaymeen
Fataawa Ramadhaan – Volume 2, Page 861, Fatwa No.846
Fiqh al-‘Ibaadaat – Page 208