What is the ruling on donating to mosques built on state-owned land without obtaining the necessary official approvals, and is it permissible to pray in them?

Building mosques on lands not owned by anyone, but rather belonging to the state, is permissible and مشروع (legitimate), provided it does not cause harm to others, such as blocking or narrowing their path, and provided there is a need for it among the people. The permission of the Imam is not required in this case.

Ibn Qudamah said: "If one builds in a wide path in a place where the construction does not cause harm, for the benefit of Muslims, such as building a mosque needed for prayer... then there is no liability upon him, and it is the same whether the Imam permits it or not." Ibn Taymiyyah narrated from Ahmad that he permitted building a mosque in a wide path that does not cause harm if there is a need for it among Muslims, and he did not stipulate the permission of the Imam.

However, if the construction is done on land owned by a person or persons without their permission, it is not permissible.