---
title: "San Ildefonso 2026: when and where it's a public holiday — festivos.io"
description: "San Ildefonso is a local holiday in 18 municipalities, accounting for 175,358 residents in the 2025 register. In 2026 it falls on 23 January."
source: "https://festivos.io/en/holiday/san-ildefonso"
---

# San Ildefonso

San Ildefonso is a local holiday in 18 municipalities — 175,358 residents in the 2025 register. In 2026 it falls on 23 January; below, where and when it's celebrated.

- **Level:** Local holiday
- **Date 2026:** Friday 23 January
- **Municipalities:** 18
- **Residents · 2025 register:** 175,358
- **Where most:** Castilla y León (9)

## San Ildefonso in the working calendar

In 2026, the dataset records San Ildefonso as a local holiday in 18 municipalities, accounting for 175,358 residents in the 2025 register. The most common date is 23 January 2026. 1 municipalities set it on another date.

This comparison uses only the official working calendars incorporated into the dataset for each year.

## Demographics of the covered population

Age, citizenship, birthplace and average-age structure from the 2025 Annual Population Census.

| Demographic profile | % |
| --- | --- |
| Women / men | 51.6% / 48.4% |
| Aged 0–14 | 14.6% |
| Aged 15–64 | 66.9% |
| Aged 65+ | 18.5% |
| Foreign citizenship | 8.6% |
| Born outside Spain | 12.4% |
| Weighted mean age | 43 years |


### How it differs from its surroundings

Comparison with Spain and with the aggregate of the 5 regions where it is observed. All five comparisons are population-weighted and use only the 2025 Annual Census. A positive sign means the covered population has a higher value than the benchmark.

| Demographic profile | Covered population | Compared with Spain | Compared with its 5 regions |
| --- | --- | --- | --- |
| Aged 0–14 | 14.6% | +1.7 pp | +1.4 pp |
| Aged 65+ | 18.5% | -2.3 pp | -1.8 pp |
| Foreign citizenship | 8.6% | -5.4 pp | -4 pp |
| Born outside Spain | 12.4% | -6.8 pp | -4.9 pp |
| Weighted mean age | 43 years | -1.6 years | -1.3 years |

The largest difference from Spain is in “Born outside Spain”: -6.8 pp.

Sex comes from the 2025 municipal register; all other metrics come from the 2025 Annual Census. Each percentage uses the total from its own statistical operation. [INE municipal tables 68535 and 68541](<https://www.ine.es/dynt3/inebase/index.htm?capsel=11532&padre=11555>).

## Dates of San Ildefonso

In 2026 it falls on Friday 23 January in most municipalities. 1 move it to another date (when it lands on a weekend or by local agreement).

| Year | Main date | Municipalities |
| --- | --- | --- |
| 2024 | Tuesday, 23 January | 11 |
| 2025 | Thursday, 23 January | 15 |
| 2026 | Friday, 23 January | 18 |

## Official sources

Official documents linked by the 2026 records. Dates can vary by territory; each municipality page preserves its specific source.

Population: official municipal-register figures at 1 January 2025. [INE](<https://www.ine.es/dyngs/INEbase/operacion.htm?c=Estadistica_C&cid=1254736177011&idp=1254734710990>).

[INE municipal tables 68535 and 68541](<https://www.ine.es/dynt3/inebase/index.htm?capsel=11532&padre=11555>).

- [Comunidad de Madrid — Festivos locales (datos abiertos)](<https://datos.comunidad.madrid/dataset/f160eb6c-6715-471e-9bc0-38497aae950f/resource/ba59e7e8-3d8d-4221-a5fa-b5e78b82707f/download/festivos_locales.csv>)
- [Gobierno de Aragón — Calendario laboral (Aragón Open Data)](<https://opendata.aragon.es/datos/catalogo/dataset/f861c5f7-5424-4b3c-90bf-a6d2c2f5b0bd/recurso/5ff8c1f8-fb7e-4343-abba-eb7dbd796dbc/descarga/festivos_aragon_2026_completo.csv>)
- [Junta de Andalucía — Calendario de fiestas locales (datos abiertos)](<https://datos.juntadeandalucia.es/api/v0/work-calendar/all?format=csv>)
- [Junta de Castilla y León — Fiestas locales (datos abiertos)](<https://analisis.datosabiertos.jcyl.es/api/explore/v2.1/catalog/datasets/fiestas-locales-calendario-de-fiestas-de-caracter-local/exports/csv?where=fecha_fiesta%3E%3D%272026-01-01%27+and+fecha_fiesta%3C%3D%272026-12-31%27>)
- [Junta de Comunidades de Castilla-La Mancha — Calendario de fiestas locales (DOCM/datos abiertos)](<https://docm.jccm.es/docm/verArchivoHtml.do?ruta=2025/12/12/html/2025_9468.html&tipo=rutaDocm>)

## 18 municipalities celebrate San Ildefonso

Its local holiday in 2026, by region. Each municipality links to its annual record and the available official source.

Together, they account for 175,358 residents in the INE municipal register at 1 January 2025.

**Castilla y León** (9): Bercial, Camponaraya, Cobos de Fuentidueña, Donjimeno, Perosillo, Real Sitio de San Ildefonso, San Miguel de Serrezuela, Torregamones, Villaralbo

**Castilla-La Mancha** (5): Argés, Herreruela de Oropesa, Mata, La, Toledo, Villavaliente

**Andalucía** (2): Mairena del Aljarafe, Peligros

**Aragón** (1): Cabañas de Ebro

**Comunidad de Madrid** (1): Collado Mediano


## About San Ildefonso

### When is San Ildefonso in 2026?

In 2026, San Ildefonso is mainly celebrated on 23 January 2026 (Friday). Some municipalities move it to another date on the working calendar.

### In how many municipalities is San Ildefonso a holiday?

It's a local holiday in 18 municipalities in 2026, accounting for 175,358 residents in the 2025 register; mostly in Castilla y León (9 municipalities).

### Is San Ildefonso a national holiday?

No. San Ildefonso is a local-level holiday: it's only a non-working day in the municipalities that set it as their local festival; each keeps its official source.


## Other holidays

- Saint Isidore the Laborer (488 municipalities)
- San Roque (278 municipalities)
- Segona Pasqua (189 municipalities)
- Martes de Entroido (186 municipalities)
- San Isidro Labrador (163 municipalities)
- San Blas (151 municipalities)
- San Vicente Ferrer (142 municipalities)
- San Pedro (136 municipalities)

Per-municipality data with its official source (regional gazette). Every date is verifiable on the municipality page. Data from festivos.io — CC BY 4.0.

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Data: festivos.io — CC BY 4.0. Official source: State Official Gazette (BOE) and regional gazettes (Law 37/2007).