The Princely State of Mahlog, also known as Mailog, was amongst main states during the rule of the British Empire in India. During the early 19th century, the region was appointed as one of the princely states of India under the indirect rule of the British administration. The region was scattered over a total area of 49 sq km and it was merged with Himachal Pradesh state in 1948. The region comprised of a total population of 27,529 in the year 1941. The Princely State of Mahlog was incorporated as a part of the Punjab States Agency. The capital of the former native state was located at Patta. The region included around 179 villages and was among the 18 Shimla Hill States.

The princely state was located approximately 30 miles southwest of Shimla. It was bounded by Baghal in the north; by Kunihar in the northeast; by Patiala in the southeast and south; by Kuthar in the southeast; and by Nalagarh in the west. An enclave of Nalagarh, which included the villages of Jamrari, was incorporated in the borders of Mahlog state.

History of Princely State of Mahlog
The Rajputs from Ajodhia was ruling family of Mahlog state. The seventh raja of Bhowana, Uttam Chand, was overpowered and expelled by the Raja of Sirmur. However with the support of the Raja of Keonthal, who was his father-in-law, he re-conquered a portion of his territory and renamed it as Mahlog. It was seized, with most of the Shimla Hill States, by Nepal between 1803 and 1815. The region was restored to the original ruling family after the Gurkha War. The princely state of Mahlog ranked ninth among the Shimla Hill States, until the abolition of the separate agency in the year 1936. Later the state was incorporated into the Punjab States Agency.

The management and administration of the princely state of Mahlog was earlier entrusted to a council, but was later put under the control of a manager from the year 1907. Mahlog was one of the original constituent members of the Chamber of Princes, a number of smaller states indirectly represented by 12 princes who were elected periodically by them. According the Attachment Scheme of 1943, the state of Mahlog was attached with Nalagarh, under the plan proposed by the British Resident for the Punjab States on 17 April 1944. The native ruler of the princely state held the title of Thakor.

After the withdrawal of the British and the independence of India on 15th August 1947, the last native ruler of the princely state of Mahlog acceded his state to the newly formed Union of India, also known as the Dominion of India in 1948.