Methodology

How the official polling-station results become the map: what is counted, how the territory is grouped into nations and what limits the data have.

Elections

General elections to the Congress of Deputies: November 2011, December 2015, June 2016, April and November 2019, and July 2023. The Senate is not included.

Nations

The map reads the State as a State of nations. Each autonomous community belongs to a nation; nations made up of several communities have internal parts, such as EAE and Nafarroa in Hego Euskal Herria.

Only territory that votes for the Spanish Congress is included: from Euskal Herria, Hego Euskal Herria (Iparralde votes in France), and from the Països Catalans, the three communities in the State (the Franja de Ponent stays within Aragón). Asturias, Cantabria and León are in the rest of the State. This is an editorial table and can be revised.

What is counted

• Voters = votes for candidates + blank votes + spoiled votes. Turnout = voters / electorate.
• Each party's percentage is calculated over the votes for candidates, without blank or spoiled votes. That is why it does not match the official percentage, which is calculated over valid votes (including blank votes).
• The vote from abroad (CERA, residents abroad) is not assigned to any section or municipality and is left out, including from the province, community, nation and State totals.
• Everything is added up from the polling station: section, municipality, province, community, nation and State.
• Merged municipalities are shown as they are today in every election: Oza-Cesuras (Oza dos Ríos and Cesuras, 2013) and Cerdedo-Cotobade (Cerdedo and Cotobade, 2016).

Parties

Up to the autonomous community, each party appears under the name it stood with there (PSC, PSdeG-PSOE, EH Bildu…). In nations made up of several communities and in the State, they are grouped under the State-wide party they belong to, as set by the Ministry itself: PSC, PSdeG-PSOE and PSOE are added up as PSOE.

For changes (▲▼) from the previous election, the same party is recognised even if its name changes (ERC-SOBIRANISTES and ERC, for example). Party colours come from our own table.

Map layers

• Winner: the party with the most votes in each area.
• Close seats (by province only, as provinces are the constituencies): votes the next party was short of taking the last seat from whoever won it: 1,000 or less, 1,000–5,000, 5,000–10,000, 10,000–20,000 and over 20,000.
• Turnout: 58 % or less, 58–64, 64–70, 70–76 and over 76 %.
• Blocs: investiture against right, at every level; in provinces, by the last seat. See «Blocs» below.

Seats

Seats are the official ones for each constituency (the province; Ceuta and Melilla, one each), published by the Ministry of the Interior. Those of a community, a nation or the State are the sum of their provinces; 350 in total. Municipalities and sections have no seats of their own, so none are shown for them.

For the last seat in each province, the allocation is recalculated with the D'Hondt method: parties with at least 3 % of the province's valid votes (including blank votes) and, in a tie, the seat goes to the one with more votes. Here the vote from abroad (CERA) is included, because the official allocation includes it. The result matches the official seats in every province and election. The margin is how many more votes the party with the best chance needed to take the last seat from whoever won it, with all other votes unchanged.

Blocs

The Blocs layer splits the parties into two blocs, those of the 2023 investiture (our own table, which can be revised):

• Investiture bloc: PSOE (with PSC, PSdeG-PSOE, PSE-EE…), SUMAR, EH Bildu, EAJ-PNV, ERC, Junts, BNG and Coalición Canaria.
• Right-wing bloc: PP, VOX and UPN.
• Predecessors, in elections before 2023: those of SUMAR (Podemos and its alliances, IU, EQUO, Más País, Compromís and MÉS per Mallorca), those of Junts (CiU, DL and CDC), Amaiur (EH Bildu), Nós (BNG) and Navarra Suma (UPN).
• Others: the rest, such as Ciudadanos, UPyD, Geroa Bai, the CUP, the PRC or Teruel Existe.

In provinces, which are the constituencies, the map colours the bloc that won the last seat, more intense the more votes the other bloc was short of taking it (those of its party with the best chance): 5,000 or less, 5,000–10,000, 10,000–20,000 and over 20,000; in grey, if it went to a party outside both blocs. At the other levels (nation, community, municipality and section), the bloc with most votes, more intense the larger its lead over the other: 5 points or less, 5–10, 10–20 and over 20. The Seats tab shows each bloc's seats; the Results tab, its votes.

Trend

The Trend tab shows how each area has voted in the six elections, from the State down to the municipality (sections change from year to year and cannot be compared). Each line is a party, even if its name changes (shown with its latest name); parties that reached 4 % at least once are shown, seven at most. If two candidacies of the same party stand in one election, the one with more votes counts. With the Blocs layer, one line per bloc.

Territory and census sections

• Census sections: the INE publishes the section boundaries as of 1 January each year. Each election is drawn with the year that best matches the sections of its polling stations: November 2011 → 2012; December 2015 → 2015; June 2016 → 2016; April 2019 → 2019; November 2019 → 2020; July 2023 → 2024.
• Municipalities: INE boundaries from 2025. Provinces, communities and nations are made by joining their municipalities.
• Boundaries are simplified so that the website loads quickly, without opening gaps between neighbouring areas.
• Common land that belongs to no municipality (such as the Bardenas Reales) has no voters and is shown in grey.

Place names

Names of municipalities, provinces and communities are in the local language, in every language of the website: those of the INE (in bilingual municipalities, the local form) and, in Hego Euskal Herria, the official Basque names. Party names are those of the Ministry.

Known limits

• No vote from abroad (CERA), except for the last seat: totals are slightly lower than the official ones.
• Percentages over votes for candidates, not over valid votes.
• In 2015, in the polling stations of about 2,200 municipalities, the Ministry's files do not agree with each other: the total of votes for candidates does not match the sum of each party's votes (43,289 votes across the State, 0.17 %). Percentages are calculated over the sum of the parties (the votes that allocate seats) and turnout over the polling-station totals.
• Section boundaries change from year to year: the same section may not be comparable between elections. That is why sections show no changes.
• Changes (▲▼) always compare with the previous general election.

Checks

Automated tests check, for every version, that Congress adds up to 350 seats, that they match the official 2023 seats and that the votes at each level add up to the same as those at the level below.