Women Riding Horses

As Muslims, modesty and chastity are integral aspects of our Deen and they are from amongst the key factors as to why in Islaam, women are commanded to remain in the confines of their homes and take care of their domestic affairs and household chores. Up to a great extent a Muslim woman’s beauty, dignity and honor are placed in her modesty and chastity and the easiest yet indisputably most effective way, if not the only way for her modesty and chastity to be safeguarded is by her remaining within the confines of her home. In this way she will be protected from many evils such as the eyes of strange men falling upon her. In this way it is more likely for her to remain chaste and for her modesty to be upheld. Furthermore, the Shariah has strongly discouraged all those factors which potentially could be a means of her modesty and chastity being compromised or even eradicated.

The Shariah has taken into consideration the chastity and modesty of women to such an extent that the Shariah has not placed any financial responsibilities upon them. Hence, there is no real need for them to leave their homes to work etc. 

Now, coming to your specific question: Generally, when going horse riding, the rider is required to dress in a certain way, with tight-fitting clothing (clothing which reveals the body shape) etc. Over and above,  for women to go horse riding, they will have to leave their homes and expose themselves before strange men, whereas the Qur’an and Ahaadith of Rasulullah (Sallallahu Alaihi Wasallam) command women to remain within the confines of their homes and not venture out of their home unless for a valid need. Furthermore, there is a narration wherein it is mentioned:

لعن الله الفروج على السروج

Allah Ta’ala has cursed women who sit on saddles (i.e. who ride on horse-back).

Note: Even though the words of the above narration has been declared a fabrication, the Hanafi jurists say ‘The meaning of this Hadith is sound’ as it conforms to the general ruling mentioned in the following Hadith that warns against women imitating men: 

“Nabi (sallallahu ‘alayhi wa sallam) cursed those men who imitate women and those women who imitate men.”
(Sahih Bukhari, Hadith:  5885)

These are some of the reasons as to why the Fuqaha (Jurists) have mentioned that it is not permissible for women to ride a horse except at times of necessity.

In brief, women are prohibited from riding horses when done for leisure and amusement or when done with the intention of adorning themselves and displaying themselves before men. If there is a necessity where only horses are available as conveyances and a woman mounts a horse intending to undertake a journey for religious purposes, such as Hajj, Umrah, etc, then there would be leeway for doing so, provided she observes Purdah and is accompanied on the journey by her husband or any other male Mahram.