This dataset covers 2476–2479 Polish municipalities and cities (dependent on the year) over a period from 2004 when Poland joined the EU to the pre-COVID-19-pandemic 2019. The created 113 yearly panel variables include budgetary, electoral competitiveness, and European Union funded investment drive data. While the dataset has been created out of publicly available sources, their use requires advanced knowledge of budgetary data and their classification, as well as data gathering, merging, and clearing, which required many hours of work over a year. Fiscal variables were created out of raw data of over 25 million subcentral governments records. They were sourced from Rb27s (revenue), Rb28s (expenditure), RbNDS (balance), and RbZtd (debt) forms, which are reported quarterly by all subcentral governments to the Ministry of Finance. These data were aggregated according to the governmental budgetary classification keys into ready-to-use variables. Furthermore, these data were used to create original EU-financed local investment drives proxy variables based on large investments in general and in sports objects in particular. Moreover, subcentral electoral data from 2002, 2006, 2010, 2014, and 2018 were sourced from the National Electoral Commission, mapped, cleared, merged, and used to create original electoral competitiveness variables. This dataset can be used to model different aspects of fiscal decentralization, political budget cycles, and EU-funded investment in a large sample of local government units.