The House Church is the assembling of fellow Christian believers in a member's home. It was practiced in the early days of the Church, as cited in the Book of Acts. It is also a continuing phenomenon in the United States. the illegal house churches, however, in the former Soviet Union, received severe sanctions, even to the point where dwellings were bulldozed to the ground.
Because churches have to be registered with the state in the People's Republic of China, (the Threefold Church) if one wants to avoid this potentially incrimination documentation, sometimes house churches are thereby formed. The congregants will risk arrest rather than agree to the state's required institutions' obedience to the Communist government as final authority (even over the reign of the Lord Jesus Christ). Many languish to this day in prisons, where they are treated harshly as they continue to exercise their adamant faith, not unlike Watchman Nee.
Today, the underground churches are quite large, mostly in the cities like Shanghai, that are mostly
in the capitalist enterprise zones thrive, but they know they are on
tenuous ground. They've come around full circle realizing that material
gains do not help one's soul.
Christians in Muslim countries are even more in a position to go underground, worshiping in their house churches. The U.S. has special organizations, that have websites, to help in this like Cyber Missions and Christian Aid, and Mission Frontiers. U.S. Pastor Saeed Abedini is imprisoned as of 2013 in Iran, and near death for helping these underground churches.
Even in the free world, a house church can allow one the opportunity to avoid denominational ties involving adherence to doctrines knotted many times more to traditions than to truth. It also gives anitinerant's preacher his opportunity to minister with his charismatic gifts without subjection to rules of certain seminaries. These regulations, if disobeyed by the denominational licensed, can cause the loss of their official standing.
Today, previous mainland China House Church pastor Bob Fu lives in Midland, Texas after escaping via a pre-PRC Hong Kong route. He and his wife, Heidi Cai run China Aid. They have helped the blind activist, Chen Guangheng in his plight. They, too, are trying to get 'Rule of Law' to advance the various Human Rights causes.
People fed up with the denominational fragmentation of the church, and over-institutionalized dogma have become enthusiastic in the United States in this area, too. There is a correlation with home school parents and children and home church growth.
There are plenty of online resources for them in the U.S.: