I know more Vaishanvas and Shaivas exist in South India and Shaktas are more prominent in the east,But in North what are the major denominations of Hindus?
No hard numbers are available. Only Vaishnavites seems to continue to exist as sects/subsects/sampradayas in significant numbers. Other sects like Shaivism and Shaktism do not have large following any more.
Non-Sectarian worship of Rama, Krishna, Siva, Hanuman, Durga, Kali, Murugan, Ganesa, Iyappan et al has large following. Sai Baba is also big.
In North India it would be Rama, Krishna, Siva (with their spouses) and Hanuman.
I assume the statistics below includes both sectarian and non-sectarian worshipers:
According to a 2010 estimate by Johnson and Grim, the Vaishnavism tradition is the largest group with about 641 million or 67.6% of Hindus. In contrast, Jones and Ryan estimate Vaishnavism to have perhaps 200 million followers, and it being the second largest tradition of Hinduism after Shaivism.