-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0000072741-10-000050.txt : 20100202
<SEC-HEADER>0000072741-10-000050.hdr.sgml : 20100202
<ACCEPTANCE-DATETIME>20100202152240
ACCESSION NUMBER:		0000072741-10-000050
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100129
FILED AS OF DATE:		20100202
DATE AS OF CHANGE:		20100202

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LaVecchia Jean M
		CENTRAL INDEX KEY:			0001415289

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05324
		FILM NUMBER:		10566705

	MAIL ADDRESS:	
		STREET 1:		107 SELDEN STREET
		CITY:			BERLIN
		STATE:			CT
		ZIP:			06037

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NORTHEAST UTILITIES
		CENTRAL INDEX KEY:			0000072741
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC SERVICES [4911]
		IRS NUMBER:				042147929
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE FEDERAL STREET
		STREET 2:		BUILDING 111-4
		CITY:			SPRINGFIELD
		STATE:			MA
		ZIP:			01105
		BUSINESS PHONE:		8606655000

	MAIL ADDRESS:	
		STREET 1:		107 SELDEN ST
		CITY:			BERLIN
		STATE:			CT
		ZIP:			06037-1616

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NORTHEAST UTILITIES SYSTEM
		DATE OF NAME CHANGE:	19961121
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>main4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-01-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000072741</issuerCik>
        <issuerName>NORTHEAST UTILITIES</issuerName>
        <issuerTradingSymbol>NU</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001415289</rptOwnerCik>
            <rptOwnerName>LaVecchia Jean M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O NORTHEAST UTILITIES</rptOwnerStreet1>
            <rptOwnerStreet2>107 SELDEN STREET</rptOwnerStreet2>
            <rptOwnerCity>BERLIN</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06037</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP-Human Resources</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Shares, $5.00 par value</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>27324.0</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Shares, $5.00 par value</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2323.0</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>401K Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Shares</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-01-29</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>63.0</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>22.88</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>63.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>444.0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Includes restricted share units and dividend equivalents thereon.</footnote>
        <footnote id="F2">Shares held in trust under the Northeast Utilities Service Company 401K Plan, a qualified plan, as of January 29, 2010, according to information supplied by the Plan's recordkeeper.</footnote>
        <footnote id="F3">Matching contribution of reporting person's deferred compensation in 2009 under the Northeast Utilities Deferred Compensation Plan for Executives, a non-qualified deferred compensation plan, that are nominally invested as Common Shares (hereby referred to as phantom shares).  While the average price of the matching contributions was $22.88, the actual price was determined on the applicable payroll date on which the deferred compensation contribution was made.  Each phantom share represents the right to receive the cash value of one share of NU common upon a distribution event, following vesting. Additional phantom shares are issued upon the automatic reinvestment of dividend-equivalents exempt from line item reporting under SEC Rule 16a-11.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Jean M. LaVecchia, By:  O. Kay Comendul/POA</signatureName>
        <signatureDate>2010-02-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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