Gurdwara Sri Reetha Sahib is located in an area of outstanding beauty at the foothills of the himalayas.
Sri Guru Nanak Sahib Ji had an encounter here with Nath yogis whom he tried to bring to the path of active humanitarian service along with remembrance of God's name.
The hindu yogis uncharitably refused to provide food for Bhai Mardana who was hungry.
Guru Nanak miraculously made the normally bitter fruit of a Reetha (soapnut) tree sweet for Bhai Mardana so he could eat.
A soapnut tree (not the original one) is still here and Sikhs are given the prashad of sweet soapnuts.
However, the common belief that the nuts of only the one branch, under which the Guru had sat, are sweet is not true. Nor are all the nuts given as prasad from this one tree.
About ten kilometers from the Grudwara, there is a tract of land where such trees are grown and their fruit is collected and brought to replenish the Gurdwara's stock of prasad.
It is called Nanak Bagichi (lit. Nanak's garden).
The Gurdwara, also known as Gurdwara Meetha Reetha Sahib, is located at the confluence of the Lodhiya and Ratiya rivers.
It was constructed in the year 1960 and is situated near the Deyuri village.
Due to its religious background this place is considered as a holy place for Sikhs. Some Reetha trees are still here in the premises of the Gurdwara.
On the day of Vaisakhi Purnima, the holy day of the Sikhs, a fair is held in the premises of Gurdwara.
Source: https://www.discoversikhism.com/sikh_gurdwaras/gurdwara_sri_reetha_sahib.html
