Eastern Ukraine
According to a 2016 survey of religion in Ukraine held by the Razumkov Center, 73.5% of the population in Eastern Ukraine were Christians (63.2% Eastern Orthodox, 8.1% simply Christians, 1.0% Protestants, and 0.3% Latin Rite Catholics), 0.5% were Muslims, 0.3% were Jewish, and 0.3% were Hindus. Not religious and other believers not identifying with any of the listed major religious institutions constituted about 24.7% of the population. It also showed that approximately 55.6% of the population of eastern Ukraine (which in Razumkov's mapping excluded Donbass and consisted of the regions immediately to the west of it) declared to be believers, while 13.4% declared to be undecided or non-believers, and 3.5% declared to be atheist. 
A 2007 survey by the Razumkov Centre asked "Would you like to have your region separated from Ukraine and joined another state?" In eastern Ukraine, 77.9% of respondents disagreed, 10.4% agreed, and the rest were undecided. 
In a poll conducted by the Kyiv International Institute of Sociology in the first half of February 2014, 25.8% of those polled in East Ukraine believed "Ukraine and Russia must unite into a single state", nationwide this percentage was 12.5%.
Ukrainian Orthodox Church (Moscow Patriarchate)
The number of parishes statistics seems to be more reliable and consistent even though it may not necessarily directly translate into the numbers of adherents. By number of parishes and quantity of church buildings, the UOC (MP)'s strong base is central and northernwestern Ukraine. However, percentage wise (with respect to rival Orthodox Churches) its share of parishes there varies from 60 to 70 percent. At the same time, by percentage alone (with respect to rival Orthodox Churches) the urban russophone southern and eastern Ukrainian provinces peak with up to 90 percent of church buildings. The same can be said about Transcarpathia, although there the UOC's main rival is the Greek Catholic Church and thus in all its share is only 40 percent. The capital Kiev is where the greatest Orthodox rivalry takes place, there the UOC (MP) has only half of the Orthodox communities. The only place where the UOC (MP) is a true minority, in both quantity, percentage and support are the former Galician provinces of Western Ukraine. There the total share of parishes does not exceed more than five percent. The UOC (MP) does not have any parishes abroad, as its followers identify themselves under the same umbrella as those of the Russian Orthodox Church.