Critical response
Mare of Easttown received critical acclaim. On review aggregator Rotten Tomatoes, the series has an approval rating of 95% based on 128 reviews, with an average rating of 8.1/10. The website's critics consensus reads, "Grounded by a career-best Kate Winslet, Mare of Easttown's ambitions at times exceed its reach, but its central mystery is supported by such strong sense of place and character it hardly matters." On Metacritic, the series has a weighted average score of 81 out of 100 based on reviews from 42 critics, indicating "universal acclaim".
Winslet received widespread praise for her performance, including from Lucy Mangan of The Guardian who wrote, "If you can have a defining performance this late in a career, this is surely Winslet's. She is absolutely wonderful." Alex Abad-Santos of Vox described Winslet's performance as "mesmerizing", adding that "she allows us to see the ugliness Mare is capable of and how obsessive, perhaps even abusive, she can be when she's threatened." The Wall Street Journal's Dorothy Rabinowitz noted "Winslet's eloquent command of the role is obvious from the outset". Ben Travers of IndieWire wrote, "Winslet's immersed performance could carry a far lesser work by itself", while adding that her East American dialect is "convincing and her physical work is flawless." Richard Roeper of the Chicago Sun-Times declared, "Winslet adds to a long list of magnificent, disappear-into-the-character performances...one of the most resonant performances of her career." Caryn James of the BBC wrote, "Winslet makes an unglamorous return to TV...and her fierce, ordinary heroine is gloriously real."
Inkoo Kang of The Hollywood Reporter gave it a mostly positive review describing it as "uneven, but masterfully suspenseful". Kang compared the series with British crime drama Happy Valley, a comparison echoed by Fiona Sturges of The Independent, who wrote that "addiction, abuse and death were woven into the fabric of life" in both dramas, while acknowledging similarities between both shows' protagonists. The New York Times was dismissive in its review, with television critic Mike Hale writing: "Some style in the direction or honest feeling in the screenplay could have mitigated the dreariness, but 'Mare' doesn't offer much beyond Ben Richardson's burnished cinematography." A plot twist in the final episode received lukewarm reviews from various outlets. For The A.V. Club, Joshua Alston wrote, "While [the final episode] is a triumphant conclusion to Mare's emotional arc, as a conclusion to a mystery, it's a mixed bag [...] the whole thing just feels arbitrary and confusing and lacks the emotional logic this show is normally so good at." In Decider, Sean T. Collins agreed but praised the leads' performances, writing, "The resolution of the mystery is a bit 'twists and fake-outs for twists' and fake-outs' sake.' But each new revelation came with an emotionally devastating payload for the characters, with Winslet and Nicholson in particular doing their best work of the series."
Critics and viewers have also particularly praised the series and Winslet for convincingly replicating the Philadelphia regional accent, an oddity in mainstream media. The specific version of the Philadelphia accent is known as the "Delco accent", after Delaware County to the southwest of Philadelphia. The characters' accents, along with their fondness for Wawa, were parodied in a May 2021 Saturday Night Live sketch.
