NORTHWEST NATURAL GAS CO

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

General form for quarterly reports under Section 13 or 15(d)

Results of Operations and Financial Condition

Other Events

General form for quarterly reports under Section 13 or 15(d)

Results of Operations and Financial Condition

Annual Report Scanned (Paper)

Other Events

Annual report pursuant to Section 13 or 15(d)

Results of Operations and Financial Condition

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers: Compensatory Arrangements of Certain Officers

General form for quarterly reports under Section 13 or 15(d)

Results of Operations and Financial Condition

Other Events

Other Events

General form for quarterly reports under Section 13 or 15(d)

Results of Operations and Financial Condition

Other Events

General form for quarterly reports under Section 13 or 15(d)

Results of Operations and Financial Condition

Annual Report Scanned (Paper)

Annual report pursuant to Section 13 or 15(d)

Results of Operations and Financial Condition

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers: Compensatory Arrangements of Certain Officers

Other Events

General form for quarterly reports under Section 13 or 15(d)

2.02,9.01

Regulation FD Disclosure

5.02,7.01,9.01

Automatic Shelf Registration

Prospectus Supplement for Delayed or Continuous Offering

General form for quarterly reports under Section 13 or 15(d)

General form for quarterly reports under Section 13 or 15(d)

Annual Report Scanned (Paper)

Annual report pursuant to Section 13 or 15(d)

Registration statement under Securities Act of 1933 to be offered to employees pursuant to certain plans

General form for quarterly reports under Section 13 or 15(d)

General form for quarterly reports under Section 13 or 15(d)

Annual reports of employee stock purchase savings and similar plans pursuant to Section 15(d)

General form for quarterly reports under Section 13 or 15(d)

Annual Report Scanned (Paper)

Prospectus Supplement for Delayed or Continuous Offering

Prospectus Supplement for Primary Offering

Free Writing Prospectus

Annual report pursuant to Section 13 or 15(d)

General form for quarterly reports under Section 13 or 15(d)

General form for quarterly reports under Section 13 or 15(d)

General form for quarterly reports under Section 13 or 15(d)

Annual report pursuant to Section 13 or 15(d)

Prospectus Supplement for Primary Offering

Free Writing Prospectus

Prospectus Supplement for Primary Offering

General form for quarterly reports under Section 13 or 15(d)

Prospectus Supplement for Delayed or Continuous Offering

Automatic Shelf Registration

Prospectus Supplement for Primary Offering

Free Writing Prospectus

Letter from the SEC

Letter from the SEC

Prospectus Supplement for Primary Offering

Free Writing Prospectus

Certification of termination of registration of a class of securities (Section 12(b))

Post-effective amendment to an automatic shelf registration statement

Notification of removal from listing and/or registration on a national securities exchange

Post Effective Amendment to S-8

Post Effective Amendment to S-8

Post Effective Amendment to S-8

Annual reports of employee stock purchase savings and similar plans pursuant to Section 15(d)

Definitive Proxy Statement

Annual reports of employee stock purchase savings and similar plans pursuant to Section 15(d)

Definitive Proxy Statement

Letter from the SEC

Correspondence with the SEC

Correspondence with the SEC

Letter from the SEC

Annual reports of employee stock purchase savings and similar plans pursuant to Section 15(d)

Correspondence with the SEC

Correspondence with the SEC

Letter from the SEC

Required Information in Proxy Statement

Definitive Proxy Statement

Annual reports of employee stock purchase savings and similar plans pursuant to Section 15(d)

Annual Report Scanned (Paper)

Definitive Proxy Statement

Definitive Proxy Statement

Definitive Proxy Statement

Definitive Proxy Statement

Definitive Proxy Statement

Definitive Proxy Statement

Definitive Proxy Statement

Definitive Proxy Statement

Preliminary Proxy Statement

Definitive Proxy Statement

Definitive Proxy Statement

Preliminary Proxy Statement

Definitive Proxy Statement

Definitive Proxy Statement

Definitive Proxy Statement

Definitive Proxy Statement

HUDDLESTON JON G

Weber David A.

Saathoff MardiLyn

DOOLITTLE LEA ANNE

ANDERSON DAVID HUGO

GIBSON C SCOTT

Wilhoite Charles A.

Rogers Melinda B.

Wasson Malia H

BOYLE TIMOTHY P

Byorum Martha L

CARTER JOHN D

DODSON MARK S

GIBSON C SCOTT

HAMACHEK TOD R

Peverett Jane L

Thrasher Kenneth

ANDERSON DAVID HUGO

HUDDLESTON JON G

Imeson Thomas J