CM1 1 postcode sector in the CM1 district

CM1 1 is a sector of the CM1 district: every postcode that starts CM1 1. It has 208 postcodes in use, 31 of them large-user postcodes. A large-user postcode is one Royal Mail gives to a single address that gets a lot of mail.

Not sure what a sector is? UK postcode format explained.

Every postcode in the CM1 1 sector, by flood risk

Map of every postcode in the CM1 1 sector, by flood risk Of the 208 postcodes in the CM1 1 sector that ONS places, 6 have a home or business at high risk, 13 are at medium risk at worst, 16 are at low risk at worst and 173 are not on the Environment Agency's at-risk list. One group of postcodes at high or medium risk is outlined: 5 postcodes at high or medium risk. Places named: Chelmsford. Drawn over roads, rivers and built-up areas. North is up; the scale bar is 500 m. A1016A138 CM1 1AF: not on the flood risk listCM1 1AG: not on the flood risk listCM1 1AH: not on the flood risk listCM1 1AN: not on the flood risk listCM1 1AP: not on the flood risk listCM1 1AQ: not on the flood risk listCM1 1AT: not on the flood risk listCM1 1AU: not on the flood risk listCM1 1AW: not on the flood risk listCM1 1BA: not on the flood risk listCM1 1BB: not on the flood risk listCM1 1BS: not on the flood risk listCM1 1BY: not on the flood risk listCM1 1DB: not on the flood risk listCM1 1DD: not on the flood risk listCM1 1DG: not on the flood risk listCM1 1DL: not on the flood risk listCM1 1DR: not on the flood risk listCM1 1DU: not on the flood risk listCM1 1DW: not on the flood risk listCM1 1DX: not on the flood risk listCM1 1EA: not on the flood risk listCM1 1EH: not on the flood risk listCM1 1EQ: not on the flood risk listCM1 1ER: not on the flood risk listCM1 1EW: not on the flood risk listCM1 1FH: not on the flood risk listCM1 1FR: not on the flood risk listCM1 1FW: not on the flood risk listCM1 1FZ: not on the flood risk listCM1 1GE: not on the flood risk listCM1 1GF: not on the flood risk listCM1 1GG: not on the flood risk listCM1 1GJ: not on the flood risk listCM1 1GN: not on the flood risk listCM1 1GP: not on the flood risk listCM1 1GR: not on the flood risk listCM1 1GS: not on the flood risk listCM1 1GU: not on the flood risk listCM1 1HF: not on the flood risk listCM1 1HG: not on the flood risk listCM1 1HH: not on the flood risk listCM1 1HL: not on the flood risk listCM1 1HQ: not on the flood risk listCM1 1HR: not on the flood risk listCM1 1HT: not on the flood risk listCM1 1HU: not on the flood risk listCM1 1HW: not on the flood risk listCM1 1HY: not on the flood risk listCM1 1HZ: not on the flood risk listCM1 1JA: not on the flood risk listCM1 1JB: not on the flood risk listCM1 1JD: not on the flood risk listCM1 1JE: not on the flood risk listCM1 1JG: not on the flood risk listCM1 1JJ: not on the flood risk listCM1 1JL: not on the flood risk listCM1 1JP: not on the flood risk listCM1 1JR: not on the flood risk listCM1 1JS: not on the flood risk listCM1 1JU: not on the flood risk listCM1 1LA: not on the flood risk listCM1 1LJ: not on the flood risk listCM1 1LN: not on the flood risk listCM1 1LR: not on the flood risk listCM1 1LS: not on the flood risk listCM1 1LU: not on the flood risk listCM1 1LW: not on the flood risk listCM1 1NE: not on the flood risk listCM1 1NF: not on the flood risk listCM1 1NH: not on the flood risk listCM1 1NL: not on the flood risk listCM1 1NP: not on the flood risk listCM1 1NQ: not on the flood risk listCM1 1NR: not on the flood risk listCM1 1NS: not on the flood risk listCM1 1NT: not on the flood risk listCM1 1NU: not on the flood risk listCM1 1NW: not on the flood risk listCM1 1NX: not on the flood risk listCM1 1NY: not on the flood risk listCM1 1NZ: not on the flood risk listCM1 1PE: not on the flood risk listCM1 1PG: not on the flood risk listCM1 1PH: not on the flood risk listCM1 1PJ: not on the flood risk listCM1 1PN: not on the flood risk listCM1 1PP: not on the flood risk listCM1 1PR: not on the flood risk listCM1 1PX: not on the flood risk listCM1 1PY: not on the flood risk listCM1 1PZ: not on the flood risk listCM1 1QA: not on the flood risk listCM1 1QB: not on the flood risk listCM1 1QD: not on the flood risk listCM1 1QE: not on the flood risk listCM1 1QF: not on the flood risk listCM1 1QG: not on the flood risk listCM1 1QH: not on the flood risk listCM1 1QJ: not on the flood risk listCM1 1QL: not on the flood risk listCM1 1QN: not on the flood risk listCM1 1QP: not on the flood risk listCM1 1QQ: not on the flood risk listCM1 1QR: not on the flood risk listCM1 1QS: not on the flood risk listCM1 1QT: not on the flood risk listCM1 1QU: not on the flood risk listCM1 1QZ: not on the flood risk listCM1 1RE: not on the flood risk listCM1 1RF: not on the flood risk listCM1 1RG: not on the flood risk listCM1 1RH: not on the flood risk listCM1 1RJ: not on the flood risk listCM1 1RL: not on the flood risk listCM1 1RN: not on the flood risk listCM1 1RP: not on the flood risk listCM1 1RQ: not on the flood risk listCM1 1RR: not on the flood risk listCM1 1RS: not on the flood risk listCM1 1RT: not on the flood risk listCM1 1RU: not on the flood risk listCM1 1RW: not on the flood risk listCM1 1RX: not on the flood risk listCM1 1RY: not on the flood risk listCM1 1RZ: not on the flood risk listCM1 1SA: not on the flood risk listCM1 1SD: not on the flood risk listCM1 1SE: not on the flood risk listCM1 1SF: not on the flood risk listCM1 1SH: not on the flood risk listCM1 1SJ: not on the flood risk listCM1 1SN: not on the flood risk listCM1 1SR: not on the flood risk listCM1 1SS: not on the flood risk listCM1 1SU: not on the flood risk listCM1 1SW: not on the flood risk listCM1 1SY: not on the flood risk listCM1 1TA: not on the flood risk listCM1 1TB: not on the flood risk listCM1 1TD: not on the flood risk listCM1 1TE: not on the flood risk listCM1 1TF: not on the flood risk listCM1 1TG: not on the flood risk listCM1 1TH: not on the flood risk listCM1 1TR: not on the flood risk listCM1 1TS: not on the flood risk listCM1 1TY: not on the flood risk listCM1 1UE: not on the flood risk listCM1 1UQ: not on the flood risk listCM1 1WB: not on the flood risk listCM1 1XB: not on the flood risk listCM1 1XD: not on the flood risk listCM1 1XE: not on the flood risk listCM1 1XR: not on the flood risk listCM1 1XU: not on the flood risk listCM1 1BE: low flood risk at worstCM1 1BT: low flood risk at worstCM1 1EJ: low flood risk at worstCM1 1GL: low flood risk at worstCM1 1JF: low flood risk at worstCM1 1JN: low flood risk at worstCM1 1LG: low flood risk at worstCM1 1QY: low flood risk at worstCM1 1RB: low flood risk at worstCM1 1SL: low flood risk at worstCM1 1WZ: low flood risk at worstCM1 1XF: low flood risk at worstCM1 1XG: low flood risk at worstCM1 1XL: low flood risk at worstCM1 1YQ: low flood risk at worstCM1 1BD: medium flood risk at worstCM1 1FU: medium flood risk at worstCM1 1FG: medium flood risk at worstCM1 1GH: medium flood risk at worstCM1 1LE: medium flood risk at worstCM1 1PA: medium flood risk at worstCM1 1PB: medium flood risk at worstCM1 1PU: medium flood risk at worstCM1 1SP: medium flood risk at worstCM1 1TN: medium flood risk at worstCM1 1TP: medium flood risk at worstCM1 1TQ: medium flood risk at worstCM1 1TW: medium flood risk at worstCM1 1AE: high flood riskCM1 1DH: high flood riskCM1 1DN: high flood riskCM1 1GD: high flood riskCM1 1LQ: high flood riskCM1 1SQ: high flood risk Chelmsford 5 postcodes at high or medium risk, outlined: this goes to CM1 1AE, the one with most homes and businesses at high risk5 postcodes at high or medium risk Map of every postcode in the CM1 1 sector, by flood risk Of the 208 postcodes in the CM1 1 sector that ONS places, 6 have a home or business at high risk, 13 are at medium risk at worst, 16 are at low risk at worst and 173 are not on the Environment Agency's at-risk list. One group of postcodes at high or medium risk is outlined: 5 postcodes at high or medium risk. Places named: Chelmsford. Drawn over roads, rivers and built-up areas. North is up; the scale bar is 500 m. Chelmsford
  • A home or business at high risk: 6
  • At medium risk at worst: 13
  • At low risk at worst: 16
  • At very low risk only: 0
  • Not on the at-risk list: 173
  • Outline: where 5 or more postcodes at high or medium risk lie together

Of the 208 postcodes in the CM1 1 sector that ONS places, 6 have a home or business at high risk, 13 are at medium risk at worst, 16 are at low risk at worst and 173 are not on the Environment Agency's at-risk list.

Each mark is a postcode's centre point as ONS gives it, not a building. Press one to see its postcode and open its page. A dashed outline shows where 5 or more lie within 150 metres of each other. It is not a boundary, and no boundary is drawn. Where marks overlap, the one first in the key is drawn; the counts include every postcode.

Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026, the centre point of each postcode; flood risk: Environment Agency, published 6 July 2026; roads, rivers and built-up areas: Contains OS data © Crown copyright and database right 2026. Drawn by us. Street map: Ordnance Survey, OS Open Zoomstack, Open Government Licence v3.0, drawn with MapLibre. How we use them

The postcodes at high risk

Beside each: how many of its homes and businesses the Environment Agency puts at that risk.

CM1 1DN8 at high riskCM1 1GD5 at high riskCM1 1LQ4 at high riskCM1 1AE3 at high riskCM1 1DH1 at high riskCM1 1SQ1 at high risk

Where the postcodes at high or medium risk lie together

  • 5 postcodes at high or medium risk, outlined on the map. CM1 1AE, is the one with most homes and businesses at high risk.

What do homes sell for in CM1 1?

Homes in CM1 1 sold for a typical £265,000 in the 12 months to August 2026, across 112 sales, down 8.6% on the 12 months before, HM Land Registry's figures show.

£265,000 typical price, the 12 months to August 2026
£290,000 12 months to August 2025
▼ down 8.6% on the 12 months before
  • Detached 3 sales, too few to price
  • Semi-detached £490,000 5 sales
  • Terraced £385,000 19 sales
  • Flat or maisonette £235,000 85 sales

Each bar is that kind's typical price, against the most expensive kind here.

Standard sales of homes at market value at the postcodes that start CM1 1. A typical price is the median, the middle sale, given from 5 sales or more.

How we work this out: house prices by postcode

Source: HM Land Registry Price Paid Data, files dated 28 September 2026. Contains HM Land Registry data © Crown copyright and database right 2021. This data is licensed under the Open Government Licence v3.0. How we use it

Postcodes in CM1 1

Pick a postcode to see its council and MP, broadband, flood risk, what homes sell for, council tax, the nearest schools and stations, and crime around it.

CM1 1AECM1 1AFCM1 1AGCM1 1AHCM1 1ANCM1 1APCM1 1AQCM1 1ATCM1 1AUCM1 1AWCM1 1BACM1 1BBCM1 1BDCM1 1BECM1 1BSCM1 1BTCM1 1BYCM1 1DBCM1 1DDCM1 1DECM1 1DGCM1 1DHCM1 1DLCM1 1DNCM1 1DRCM1 1DUCM1 1DWCM1 1DXCM1 1EACM1 1EBCM1 1EHCM1 1EJCM1 1ELCM1 1EQCM1 1ERCM1 1EWCM1 1FGCM1 1FHCM1 1FRCM1 1FUCM1 1FWCM1 1FZCM1 1GDCM1 1GECM1 1GFCM1 1GGCM1 1GHCM1 1GJCM1 1GLCM1 1GNCM1 1GPCM1 1GRCM1 1GSCM1 1GUCM1 1GZCM1 1HFCM1 1HGCM1 1HHCM1 1HLCM1 1HQCM1 1HRCM1 1HTCM1 1HUCM1 1HWCM1 1HXCM1 1HYCM1 1HZCM1 1JACM1 1JBCM1 1JDCM1 1JECM1 1JFCM1 1JGCM1 1JJCM1 1JLCM1 1JNCM1 1JPCM1 1JRCM1 1JSCM1 1JUCM1 1JYCM1 1JZCM1 1LACM1 1LBCM1 1LECM1 1LGCM1 1LJCM1 1LNCM1 1LQCM1 1LRCM1 1LSCM1 1LUCM1 1LWCM1 1LXCM1 1NECM1 1NFCM1 1NGCM1 1NHCM1 1NLCM1 1NPCM1 1NQCM1 1NRCM1 1NSCM1 1NTCM1 1NUCM1 1NWCM1 1NXCM1 1NYCM1 1NZCM1 1PACM1 1PBCM1 1PECM1 1PGCM1 1PHCM1 1PJCM1 1PNCM1 1PPCM1 1PRCM1 1PTCM1 1PUCM1 1PXCM1 1PYCM1 1PZCM1 1QACM1 1QBCM1 1QDCM1 1QECM1 1QFCM1 1QGCM1 1QHCM1 1QJCM1 1QLCM1 1QNCM1 1QPCM1 1QQCM1 1QRCM1 1QSCM1 1QTCM1 1QUCM1 1QYCM1 1QZCM1 1RBCM1 1RECM1 1RFCM1 1RGCM1 1RHCM1 1RJCM1 1RLCM1 1RNCM1 1RPCM1 1RQCM1 1RRCM1 1RSCM1 1RTCM1 1RUCM1 1RWCM1 1RXCM1 1RYCM1 1RZCM1 1SACM1 1SBCM1 1SDCM1 1SECM1 1SFCM1 1SHCM1 1SJCM1 1SLCM1 1SNCM1 1SPCM1 1SQCM1 1SRCM1 1SSCM1 1SUCM1 1SWCM1 1SYCM1 1TACM1 1TBCM1 1TDCM1 1TECM1 1TFCM1 1TGCM1 1THCM1 1TNCM1 1TPCM1 1TQCM1 1TRCM1 1TSCM1 1TWCM1 1TYCM1 1UECM1 1UPCM1 1UQCM1 1UWCM1 1UZCM1 1WBCM1 1WZCM1 1XACM1 1XBCM1 1XDCM1 1XECM1 1XFCM1 1XGCM1 1XLCM1 1XPCM1 1XRCM1 1XUCM1 1YQCM1 1YS

Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026. Postcodes that have ended are not listed. See all our data sources

What council am I in? The council, borough or local authority for a postcode, and the county council where there is one. What ward am I in? The ward for a postcode, with its council, constituency and parish.

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