Nigeria

…
(3) For the purpose of promoting national integration, it shall be the duty of the State to:
…
(c) encourage inter-marriage among persons from different places of origin, or of different religious, ethnic or linguistic association or ties;
… (Sec. 15)

…
(3) The State shall direct its policy towards ensuring that –
…
(h) the evolution and promotion of family life is encouraged. (Sec. 17)

(1) An appeal shall lie from decisions of the Federal High Court or a High Court to the Court of Appeal as of right in the following cases –
…
(f) decisions made or given by the Federal High Court or a High Court –
…
(iv) in the case of a decree nisi in a matrimonial cause or a decision in an admiralty action determining liability,
…
(2) Nothing in this section shall confer any of appeal –
…
(b) from an order absolute for the dissolution or nullity of marriage in favour of any party who, having had time and opportunity to appeal from the decree nisi on which the order was founded, has not appealed from that decree nisi;
… (Sec. 241)

(1) The Sharia Court of Appeal shall, in addition to such other jurisdiction as may be conferred upon it by an Act of the National Assembly, exercise such appellate and supervisory jurisdiction in civil proceedings involving questions of Islamic personal law.
(2) For the purpose of subsection (1) of this section, the Sharia Court of Appeal shall be competent to decide –
(a) any question of Islamic personal law regarding a marriage concluded in accordance with that law, including a question relating to the validity or dissolution of such a marriage or a question that depends on such a marriage and relating to family relationship or the guardianship of an infant;
(b) where all the parties to the proceeding are Muslims, any question of Islamic personal law regarding a marriage, including the validity or dissolution of that marriage, or regarding family relationship, a foundling or the guardianship of an infant;
(c) any question of Islamic personal law regarding a wakf, gift, will or succession where the endower, donor, testator or deceased person is a Muslim;
(d) any question of Islamic personal law regarding an infant, prodigal or person of unsound mind who is a Muslim or the maintenance or the guardianship of a Muslim who is physically or mentally infirm; or
(e) where all the parties to the proceedings, being Muslims, have requested the court that hears the case in the first instance to determine that case in accordance with Islamic personal law, any other question. (Sec. 262)

(1) The Sharia Court of Appeal of a State shall, in addition to such other jurisdiction as may be conferred upon it by the law of the State, exercise such appellate and supervisory jurisdiction in civil proceedings involving questions of Islamic personal Law which the court is competent to decide in accordance with the provisions of subsection (2) of this section.
(2) For the purposes of subsection (1) of this section, the sharia Court of Appeal shall be competent to decide –
(a) any question of Islamic personal Law regarding a marriage concluded in accordance with that Law, including a question relating to the validity or dissolution of such a marriage or a question that depends on such a marriage and relating to family relationship or the guardianship of an infant;
(b) where all the parties to the proceedings are muslims, any question of Islamic personal Law regarding a marriage, including the validity or dissolution of that marriage, or regarding family relationship, a founding or the guarding of an infant;
(c) any question of Islamic personal Law regarding a wakf, gift, will or succession where the endower, donor, testator or deceased person is a muslim;
(d) any question of Islamic personal Law regarding an infant, prodigal or person of unsound mind who is a muslim or the maintenance or the guardianship of a muslim who is physically or mentally infirm; or
(e) where all the parties to the proceedings, being muslims, have requested the court that hears the case in the first instance to determine that case in accordance with Islamic personal law, any other question. (Sec. 277)

…
61. The formation, annulment and dissolution of marriages other than marriages under Islamic law and Customary law including matrimonial causes relating thereto.
… (Second Schedule – Legislative Powers, Part I – Exclusive Legislative List)

1. The main functions of a local government council are as follows:
…
(i) registration of all births, deaths and marriages;
… (Fourth Schedule – Functions of a Local Government Council)