| District of Castelo Branco | |
| Native Name Lang: | pt |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Portugal |
| Subdivision Type1: | Region |
| Subdivision Name1: | Centro |
| Subdivision Type2: | Historical province |
| Subdivision Name2: | Beira Baixa |
| Subdivision Type3: | No. of municipalities |
| Subdivision Name3: | 11 |
| Subdivision Type4: | No. of parishes |
| Subdivision Name4: | 160 |
| Seat Type: | Capital |
| Seat: | Castelo Branco |
| Unit Pref: | Metric |
| Area Total Km2: | 6,675 |
| Population Total: | 225916 |
| Population As Of: | 2011 |
| Population Density Km2: | auto |
| Iso Code: | PT-05 |
| Blank Name Sec1: | No. of parliamentary representatives |
| Blank Info Sec1: | 4 |
Castelo Branco District (Portuguese: Distrito de Castelo Branco pronounced as /pt-PT/) is located in Central Portugal. Its capital is Castelo Branco, which is now also its most populous city, overtaking Covilhã, which was once the largest city, in the late 2010s.
It has an area of (4th largest in Portugal), and a population of 225,916 inhabitants. It borders Spain.
The district is composed of 11 municipalities:
See main article: Castelo Branco (Assembly of the Republic constituency). |- class="unsortable"!rowspan=2|Parties!!%!!S!!%!!S!!%!!S!!%!!S!!%!!S!!%!!S!!%!!S!!%!!S!!%!!S!!%!!S!!%!!S!!%!!S!!%!!S!!%!!S!!%!!S!!%!!S|- class="unsortable" align="center"!colspan=2 | 1976!colspan=2 | 1979!colspan=2 | 1980!colspan=2 | 1983!colspan=2 | 1985!colspan=2 | 1987!colspan=2 | 1991!colspan=2 | 1995!colspan=2 | 1999!colspan=2 | 2002!colspan=2 | 2005!colspan=2 | 2009!colspan=2 | 2011!colspan=2 | 2015!colspan=2 | 2019!colspan=2 | 2022|-| align="left"| PS || style="background:#FF66FF;"|36.4 || style="background:#FF66FF;"|3 || 27.8 || 2 || 30.3 || 2 || style="background:#FF66FF;"|37.1 || style="background:#FF66FF;"|3 || 18.5 || 1 || 22.4 || 2 || 32.4 || 2 || style="background:#FF66FF;"|53.2 || style="background:#FF66FF;"|3 || style="background:#FF66FF;"|51.6 || style="background:#FF66FF;"|3 || style="background:#FF66FF;"|46.1 || style="background:#FF66FF;"|3 || style="background:#FF66FF;"|56.0 || style="background:#FF66FF;"|4 || style="background:#FF66FF;"|41.0 || style="background:#FF66FF;"|2 || 34.8 || 2 || style="background:#FF66FF;"|38.9 || style="background:#FF66FF;"|2 || style="background:#FF66FF;"|40.9 || style="background:#FF66FF;"|3 || style="background:#FF66FF;"|47.7 || style="background:#FF66FF;"|3|-| align="left"| PSD || 22.6 || 2 || align=center colspan=4 rowspan=2|In AD || 30.6 || 2 || style="background:#FF9900;"|31.2 || style="background:#FF9900;"|3 || style="background:#FF9900;"|52.1 || style="background:#FF9900;"|4 || style="background:#FF9900;"|51.8 || style="background:#FF9900;"|3 || 32.1 || 2 || 32.0|| 2 || 38.3 || 2 || 26.7 || 1 || 29.8 || 2 || style="background:#FF9900;"|37.9 || style="background:#FF9900;"|2 || align=center colspan=2 rowspan=2|In PàF || 26.3 || 1 || 27.4 || 1|-| align="left"| CDS-PP || 19.9 || 2 || 13.2 || 1 || 9.6 || || 4.7 || || 3.9 || || 7.2 || || 6.3 || || 7.1 || || 5.3 || || 8.4 || || 9.6 || || 3.7 || || 1.6|-| align="left"| AD || colspan=2| || style="background:#00FFFF;"|49.9 || style="background:#00FFFF;"|4 || style="background:#00FFFF;"|51.0 || style="background:#00FFFF;"|4 || colspan=26||-| align="left"| PRD || colspan=8| || 24.4 || 2 || 6.0 || || colspan=20||-| align="left"| PàF || colspan=26| || 35.3 || 2 || colspan=4| |-! Total seats || colspan=2|7 || colspan=10|6 || colspan=10|5 || colspan=10|4|-! colspan=33|Source: Comissão Nacional de Eleições|}