United Flight 4576 Deals & Information (2026/2027)

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United Flight 4576 Route Deals From $76

The cheapest prices found with in the last 7 days for return flights were $100 and $76 for one-way flights to Lambert-St. Louis Intl. for the period specified. Prices and availability are subject to change. Additional terms apply.

Mon, Aug 31 - Thu, Sep 3
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$100 Roundtrip, found 5 hours ago
$100
Roundtrip
found 5 hours ago
Select United flight, departing Mon, Aug 31 from O'Hare Intl. to Lambert-St. Louis Intl., returning Thu, Sep 3, priced at $100 found 5 hours ago
Mon, Aug 31 - Thu, Sep 3
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$124 Roundtrip, found 5 hours ago
$124
Roundtrip
found 5 hours ago
Select United flight, departing Mon, Aug 31 from O'Hare Intl. to Lambert-St. Louis Intl., returning Thu, Sep 3, priced at $124 found 5 hours ago
Sat, Aug 8 - Wed, Aug 12
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$156 Roundtrip, found 5 days ago
$156
Roundtrip
found 5 days ago
Select United flight, departing Sat, Aug 8 from O'Hare Intl. to Lambert-St. Louis Intl., returning Wed, Aug 12, priced at $156 found 5 days ago
Mon, Aug 31 - Thu, Sep 3
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$160 Roundtrip, found 5 hours ago
$160
Roundtrip
found 5 hours ago
Select United flight, departing Mon, Aug 31 from O'Hare Intl. to Lambert-St. Louis Intl., returning Thu, Sep 3, priced at $160 found 5 hours ago
Sat, Aug 8 - Wed, Aug 12
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$163 Roundtrip, found 5 days ago
$163
Roundtrip
found 5 days ago
Select United flight, departing Sat, Aug 8 from O'Hare Intl. to Lambert-St. Louis Intl., returning Wed, Aug 12, priced at $163 found 5 days ago
Mon, Aug 31 - Thu, Sep 3
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$171 Roundtrip, found 5 hours ago
$171
Roundtrip
found 5 hours ago
Select United flight, departing Mon, Aug 31 from O'Hare Intl. to Lambert-St. Louis Intl., returning Thu, Sep 3, priced at $171 found 5 hours ago
Sat, Aug 8 - Wed, Aug 12
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$184 Roundtrip, found 5 days ago
$184
Roundtrip
found 5 days ago
Select United flight, departing Sat, Aug 8 from O'Hare Intl. to Lambert-St. Louis Intl., returning Wed, Aug 12, priced at $184 found 5 days ago
Mon, Aug 31 - Thu, Sep 3
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$195 Roundtrip, found 5 hours ago
$195
Roundtrip
found 5 hours ago
Select United flight, departing Mon, Aug 31 from O'Hare Intl. to Lambert-St. Louis Intl., returning Thu, Sep 3, priced at $195 found 5 hours ago
Mon, Aug 31 - Thu, Sep 3
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$195 Roundtrip, found 5 hours ago
$195
Roundtrip
found 5 hours ago
Select United flight, departing Mon, Aug 31 from O'Hare Intl. to Lambert-St. Louis Intl., returning Thu, Sep 3, priced at $195 found 5 hours ago
Sat, Aug 8 - Wed, Aug 12
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$215 Roundtrip, found 5 days ago
$215
Roundtrip
found 5 days ago
Select United flight, departing Sat, Aug 8 from O'Hare Intl. to Lambert-St. Louis Intl., returning Wed, Aug 12, priced at $215 found 5 days ago
Sat, Aug 29 - Sun, Aug 30
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$217 Roundtrip, found 23 hours ago
$217
Roundtrip
found 23 hours ago
Select United flight, departing Sat, Aug 29 from O'Hare Intl. to Lambert-St. Louis Intl., returning Sun, Aug 30, priced at $217 found 23 hours ago
Mon, Aug 31 - Thu, Sep 3
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$219 Roundtrip, found 5 hours ago
$219
Roundtrip
found 5 hours ago
Select United flight, departing Mon, Aug 31 from O'Hare Intl. to Lambert-St. Louis Intl., returning Thu, Sep 3, priced at $219 found 5 hours ago
Fri, Sep 11 - Sun, Sep 13
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$228 Roundtrip, found 2 days ago
$228
Roundtrip
found 2 days ago
Select United flight, departing Fri, Sep 11 from O'Hare Intl. to Lambert-St. Louis Intl., returning Sun, Sep 13, priced at $228 found 2 days ago
Mon, Aug 31 - Thu, Sep 3
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$242 Roundtrip, found 5 hours ago
$242
Roundtrip
found 5 hours ago
Select United flight, departing Mon, Aug 31 from O'Hare Intl. to Lambert-St. Louis Intl., returning Thu, Sep 3, priced at $242 found 5 hours ago

Frequently asked questions

What route does flight number UA4576 take?
Flight number UA4576 operates non-stop from ACK to Newark, NJ Airport (EWR-Liberty Intl.). During this trip, you'll be in the air for approximately 1 hour and 40 minutes. Consider booking ahead to lock in your favorite seat.
What kind of plane is on flight number UA4576?
There's every chance you'll be cruising aboard the Canadair (Bombardier) Regional Jet 550 if you have a seat on flight UA4576. Typically, this flight leaves from Nantucket, MA Airport (ACK-Nantucket Memorial) and comes in to land at EWR.
If I am not able to travel due to COVID-19, can I change my flight to a later date?
For more info about changing your UA4576 flight with Travelocity, please visit our Customer Service Portal.