BIHAR is a state in North East India
In the 16th century, the Mughal emperor Akbar annexed Bihar and Bengal. With the decline of the Mughals, Bihar passed under the control of the Nawabs of Bengal. Thus, this period was mostly one of anonymous provincial existence.
After the Battle of Buxar (1764), the British East India Company obtained the diwani rights (rights to administer, and collect revenue or tax) for Bihar, Bengal and Orissa. From this point, Bihar remained a part the Bengal Presidency of the British Raj until 1912, when the province of Bihar and Orissa was carved out as a separate province. In 1935, certain portions of Bihar were reorganised into the separate province of Orissa.
The state of Jharkhand was carved out of Bihar in the year 2000
Initially Bihar used the Asoka capital surrounded with the title of the country as its emblem.
The actual emblem of Bihar shows a tree rising from a socle with a text in ancient Urdu, between two swastika.
The tree symbolizes the Bodhi Tree, also known as Bo (from the Sinhalese Bo). This was a large and very old Sacred Fig tree (Ficus religiosa - Moraceae) located in Bodh Gaya (about 100 km from Patna in Bihar), under which Siddhartha Gautama, the spiritual teacher and founder of Buddhism later known as Gautama Buddha, is supposed to have achieved enlightenment, or Bodhi.
The represent Dharma, universal harmony, and the balance of opposites. The word comes from the Sanskrit word svastika, composed of su (meaning ‘good’), asti (meaning ‘to be’) and the suffix ka.
As such the emblem symbolizes Bihar as the cradle of Buddhism.
According to Leithbridge  there were (at least) two ruling families in Bihar bearing heraldic symbols:
The family cognizance of the Maharaja Kumar of Hatwa consisted of a shield between two swords, with tigers as supporters and underneath the motto:
Sonbarsa Raj in Saharsa district, (Bihar) was an independent state during the British Raj. The cognizance of the ruling family was a flag bearing on it the figure of an elephant.
 Leithbridge, Sir Roper: The Golden Book of India. With an appendix for Ceylon. Sampson Low & Co.. London, 1900. XX & 366pp.