Is it permissible to pray in a mosque that has a graveyard in front of its qiblah?
Question

                We work in a company in the desert, and the closest city to us is 3 km away; in that city there is one mosque; in front of its qiblah, behind a wall, there are some graves.

Is it permissible to pray in it or not?.
Praise be to Allah.If the mosque was built 
      because of those graves, then it is not acceptable to pray in it; this is 
      like what the Jews and Christians did who used to venerate graves and 
      build places of worship over them. 
If that is not the case and 
    the mosque was not built because of those graves, then it is acceptable to 
    pray in it, but some scholars stipulate that between the wall of the mosque 
    and the graves there should be some empty space or a distance separating 
    them from one another. 
Shaykh al-Islam Ibn 
    Taymiyah (may Allah have mercy on him) said: 
Al-Aamidi and others said: 
    it is not permissible to pray in it – i.e., a mosque whose qiblah faces 
    towards graves – unless there is between the wall and the graveyard another 
    barrier. And some of them mentioned that this was stated by Ahmad. 
Al-Mustadrak ‘ala 
    Majmoo‘ al-Fataawa, 3/75 
In al-Durar al-Saniyyah 
    fil Ajwabah al-Najdiyyah (4/265) it says: 
Shaykh Muhammad ibn 
    al-Shaykh ‘Abd al-Lateef ibn ‘Abd al-Rahmaan and Shaykh Sulaymaan ibn 
    Sahmaan said: With regard to the mosque of al-Taa’if, on the northern side 
    of which there is the grave of Ibn ‘Abbaas (may Allah be pleased with him), 
    it is permissible to pray in the mosque, if a high wall has been placed 
    between the grave and the mosque, which means that the grave is outside of 
    the mosque boundary. So it is not makrooh to pray there. End quote. 
Others stipulated that the 
    wall of the mosque should be high so that the graves cannot be seen by the 
    worshippers. Shaykh Muhammad ibn Saalih al-‘Uthaymeen (may Allah have mercy 
    on him) said: 
If a person prays in a 
    mosque in front of which is a graveyard, if there is a street – for example 
    – or a full wall, so that the worshippers cannot see the graves, there is 
    nothing wrong with that. But if it is close and directly next to the mosque, 
    and there is no wall, or there is a wall but it is low and the worshippers 
    can see these graves, then it is not permissible, because the Prophet 
    (blessings and peace of Allah be upon him) said: “Do not pray towards graves 
    and do not sit on them.” Narrated by Muslim 
Liqa’ al-baab al-Maftooh, 
    137; first question 
It does not seem that what 
    is mentioned above – about the wall being high and there being empty space 
    in between – is binding, but if that is done then it is better and doing it 
    is on the safe side. Rather it is sufficient if the mosque and the graves 
    are separated by a wall which shows that the mosque is separate from the 
    graves. One of the signs of them being completely separate is that each of 
    them – the graveyard and the mosque – was built on its own land, and that 
    the mosque was not built because of the graves. If that is the case, then it 
    is permissible to pray in the mosque. 
The scholars of the 
    Standing Committee were asked: 
Some mosques and places 
    where the Eid prayers and prayers for rain (istisqa’) are offered are built 
    near graveyards in such a way that the graveyard is in the qiblah of the 
    mosque and is separated from it by only a few metres. Some of the mosques 
    are right next to the graveyards, and places where the Eid prayers and 
    prayers for rain (istisqa’) are offered are surrounded with a wall that 
    separates them from the graveyard, whilst some others do not have a wall 
    separating them from the graveyard. What is the ruling? 
They replied 
If these mosques and places 
    where the Eid prayers and prayers for rain (istisqa’) are offered were not 
    built near the graveyards because of the graveyards or to honour those who 
    were buried in them or to seek more reward for praying in them because they 
    are close to the graveyards, then building them for praying and drawing 
    closer to Allah in them is permissible, praying in them is acceptable and 
    frequenting them for the purpose of prayer and other acts of worship that 
    may be done there is something that is encouraged in Islam. If the 
    graveyards are surrounded with walls that separate them from the mosques, 
    that is sufficient. With regard to those that are not surrounded with walls, 
    walls should be built to separate them from the mosques and places where the 
    Eid prayers and prayers for rain (istisqa’) are offered. If it is possible 
    to leave empty space between the walls of the mosques and places where the 
    Eid prayers and prayers for rain (istisqa’) are offered, and the walls of 
    the graveyards, that is more on the safe side. But if the mosques were built 
    around the graveyards in order to venerate the graves, it is not permissible 
    to pray in them and they should be demolished, because building them in the 
    manner mentioned is one of the things that lead to shirk, i.e., associating 
    the occupants of the grave with Allah. And it is narrated in a saheeh report 
    that the Prophet (blessings and peace of Allah be upon him) said: “Do not 
    pray towards graves or sit on them.” It is also narrated from him in a 
    saheeh report that he said: “Those who came before you used to take the 
    graves of their Prophets and righteous men as places of worship; do not take 
    graves as places of worship for I forbid you to do that.” Both hadeeths were 
    narrated by Muslim in his Saheeh; the hadeeths concerning this matter 
    are well known. 
Shaykh ‘Abd al-‘Azeez ibn 
    Baaz, Shaykh ‘Abd al-Razzaaq ‘Afeefi, Shaykh ‘Abd-Allah ibn Ghadyaan, Shaykh 
    ‘Abd-Allah ibn Qa‘ood 
Majallat al-Buhooth 
    al-Islamiyyah, 15/78, 79 
See also the answer to 
    question no. 13490 
And Allah knows best.