Without a doubt, homeschooling is legal in all the 50 States of the U.s. But, that is just about where the similarity ends. Laws and regulations regarding homeschooling vary from state to state. Interpretations of these laws can vary from schooll district to school district. Additionally, these laws may change every year.
The National Home Education network is a wonderful resource when it comes to the legalities of homeschooling. It has a listing of the actual state laws for each state in the U.S. Reading the laws that pertain to your state is perhaps the best way to get accurate information about these laws. But, most people need to get the laws interpreted by a qualified attorney. You can get valuable information from the support group at your locality. Additionally, many state education departments have online resources that will help you in interpreting the state requirements for homeschooling. The internet is also a good source of information.
You can also check the Homeschool Legal Defense Association at hslda.org!
It is a good idea to check out your state laws regarding homeschooling before you start educating your child at home. This will prevent any nasty surprises on the way. If you have to move, you will need to be aware of any tests or exams that your child may need to take.